Bill Gates

The machine that created Microsoft's market came from Ed Roberts's MITS, founded in an Albuquerque garage in 1969 by Roberts and Forrest Mims to sell model-rocket telemetry kits, which evolved into calculator kits featured on Popular Electronics covers. Texas Instruments' decision to sell finished calculators at less than half the prevailing price devastated the kit business and left Roberts struggling under roughly a quarter-million dollars of debt, forcing the bet on a computer kit: the Altair 8800, built on the Intel 8080 and featured on the January 1975 Popular Electronics cover, sold by mail order with no screen or keyboard, programmed through front-panel switches or a serial terminal. It became the first commercially successful personal computer, its bus became the industry-standard S-100, and, as computing pioneer Harry Garland put it, the product catalyzed the entire microcomputer revolution. Its first programming language was Altair BASIC, Microsoft's founding product.

When Gates and Allen read about the Altair in January 1975, they understood that computer prices would soon fall far enough that selling software for them could be a real business, and they told MITS founder Ed Roberts they were developing a BASIC interpreter, though none existed, following the engineering custom of the trial balloon. Roberts agreed to a demonstration in March 1975, giving them weeks to deliver. Allen adapted an Intel 8008 emulator he had written for Traf-O-Data to simulate the 8080 on Harvard's PDP-10, and the pair developed and tested the interpreter there; Harvard officials were displeased but found no written policy against it, so debugging finished on time purchased from a Boston timesharing service. Monte Davidoff, a fellow student, argued for floating-point arithmetic and was hired to build it. The finished interpreter, with its own input-output system and line editor, fit in four kilobytes of memory.

Gates founded Breakthrough Energy in 2015 as an umbrella for organizations accelerating innovation in sustainable energy and other emissions-cutting technologies. At the November 2015 United Nations climate conference in Paris he announced a coalition of twenty-eight wealthy investors from ten countries, alongside a complementary initiative, Mission Innovation, in which twenty national governments pledged to double spending on carbon-free energy research. In December 2016 the effort crystallized into a one-billion-dollar Breakthrough Energy Ventures fund, backed by investors collectively worth $170 billion, including Jeff Bezos, Michael Bloomberg, Richard Branson, Ray Dalio, Jack Ma, Mark Zuckerberg, Reid Hoffman, and Meg Whitman. The fund's discipline is patience: it targets businesses where failure risk is high and the investment horizon runs twenty years, against the five-year norm of traditional venture capital. Gates, who had already committed a personal two billion dollars, argued that existing renewables like wind and solar were advancing but the scale of the challenge demanded exploring many paths.

In February 1976, after discovering that a pre-release copy of Altair BASIC had leaked and was being copied widely through the hobbyist community, Gates wrote An Open Letter to Hobbyists in the MITS newsletter. He asserted that more than ninety percent of Altair BASIC users had not paid Microsoft for it, and that such unpaid copying threatened to eliminate the incentive for anyone to develop, distribute, and maintain high-quality software. The unfairness he attacked was hobbyists gaining the benefit of authors' time, effort, and capital without paying, and the same argument led him to refuse to publish the source code, keeping the program's blueprints from being copied from library shelves into hobby machines. The letter made Gates deeply unpopular among hobbyists, many of whom saw software sharing as the culture's point, but he persisted in the conviction that developers deserved payment, a position the entire software industry eventually institutionalized.

The Road Ahead, published in November 1995 by Viking and co-written with Microsoft executive Nathan Myhrvold and journalist Peter Rinearson, summarized the personal-computing revolution and forecast a future transformed by a global information superhighway. Gates received a $2.5 million advance, with his proceeds and subsidiary-rights money donated to encourage educational technology through a foundation created by the National Education Association. The book shipped with a CD-ROM carrying the text and supplemental material, and the publisher's promotional budget of one million dollars ranked among its largest ever, rivaling the campaign for Colin Powell's memoir. The hardback treated the Internet as an important precursor of the coming highway, suggesting one could think of it as the beginning, the way the Oregon Trail prefigured the interstate; within a year the Internet's explosion forced a substantially revised trade paperback from Penguin in October 1996, promising readers a completely updated edition.

The Giving Pledge, formally announced in June 2010 by Bill Gates, Melinda French Gates, and Warren Buffett, asks the wealthy to commit the majority of their net worth, more than half, to philanthropy in their lifetimes or wills. It is a public gesture of intention rather than a legal contract, and each signer writes a letter explaining the decision; the pledge is even open to non-billionaires who plan to give away at least $500 million. The early traction was extraordinary: the first forty pledgers represented $125 billion of aggregate wealth by August 2010, and the campaign has since grown past 250 signatories from 30 countries whose combined wealth runs to roughly $600 billion. Momentum has slowed, with 113 signing in the first five years, 72 in the next five, and 43 in the five after that, and the list has occasionally purged members, removing Sam Bankman-Fried in 2022 and T. Denny Sanford in 2023.

Gates studied the philanthropy of Andrew Carnegie and John D. Rockefeller before building his own, donating Microsoft stock in 1994 to create the William H. Gates Foundation; in 2000 he and his wife combined three family foundations and donated stock valued at five billion dollars to create the Bill & Melinda Gates Foundation. By 2013 it was identified as the world's largest charitable foundation, with assets reportedly above $34.6 billion, and its structure drew on the Rockefeller model of tackling global problems governments ignore. Its program divisions span global development, global health, United States programs, and global policy and advocacy, funding fights against AIDS, tuberculosis, and malaria, vaccine campaigns to eradicate polio, sanitation and agriculture programs including Golden Rice, and family-planning access. David Rockefeller's personal generosity was a credited influence, and unlike some peers the foundation lets benefactors see how its money is spent.

Microsoft introduced its most successful office product on August 8, 1989, as a bundle of separate applications rather than the integrated single program of Microsoft Works, packaging the word processor, spreadsheet, and presentation tools customers already knew individually. The Windows version followed in October 1990 as a bundle of three applications built for Windows 3.0, and it became the vehicle by which Microsoft converted its operating-system position into applications dominance during the DOS-to-Windows transition. Excel had originally competed against the then-dominant Lotus 1-2-3 spreadsheet and eventually outsold it, while Word displaced WordPerfect as the suite era consolidated. Competitors alleged that Microsoft used inside knowledge of the DOS and Windows kernels and undocumented application programming interfaces to make Office run better than rivals' products, claims Novell pressed in court; whatever the merits, Office ended the 1990s as the dominant business suite, with market share far exceeding every competitor.

Internet Explorer began in the summer of 1994 as a project started by Thomas Reardon, built on source code licensed from Spyglass, which had developed the Mosaic browser under license from the University of Illinois. The deal promised Spyglass a quarterly fee plus a percentage of Microsoft's non-Windows revenues for the software, but Microsoft chose to give the browser away free with Windows, so the royalties never materialized; Spyglass sued, and the parties settled for eight million dollars on January 22, 1997. The first version, dubbed Microsoft Internet Explorer, shipped inside the Internet Jumpstart Kit in the Plus! pack for Windows 95 in August 1995, and subsequent versions were folded into service packs and the OEM releases of Windows 95 and later systems, embedding the browser so deeply into the platform that the practice became the core exhibit in the government's antitrust case.

Gates's most consequential personnel decision came on June 11, 1980, when he persuaded Steve Ballmer, his Harvard friend, to abandon a Stanford MBA program and join Microsoft as its thirtieth employee and first business manager. Ballmer arrived with a Harvard degree in mathematics and economics from the class of 1977 and two years as an assistant product manager at Procter & Gamble, where his office mate was Jeff Immelt, the future General Electric chief. The original terms were $50,000 in salary plus ten percent of the profit he generated, with no equity, an arrangement restructured when Microsoft incorporated in 1981, swapping the profit share for an eight percent stake that Gates funded the majority of after Allen initially objected. Ballmer went on to run operations, operating systems development, and sales, becoming the de facto number two to Gates, then president in 1998 and chief executive in January 2000, before retiring in February 2014 in favor of Satya Nadella.

The road to the antitrust trial ran through a decade of escalating scrutiny. The Federal Trade Commission opened an inquiry in 1990 into whether Microsoft was abusing its PC operating-system monopoly, deadlocked two-to-two in 1993, and closed the file; the Department of Justice under Janet Reno then opened its own investigation, producing a July 15, 1994 consent decree in which Microsoft agreed not to tie other products to Windows sales but remained free to integrate additional features into the operating system. That distinction became the battlefield: Microsoft insisted Internet Explorer was not a product but a feature it was allowed to add, while the government disagreed. With more than ninety percent of workplace PCs running its systems, Microsoft's licensing restrictions on manufacturers, its treatment of rival browsers, and its manipulation of application programming interfaces drew the government's case that bundling had unlawfully foreclosed competitors.

Microsoft was founded on April 4, 1975, in Albuquerque, New Mexico, after Paul Allen, then a programmer at Honeywell, saw the January 1975 Popular Electronics cover story on the Altair 8800 while walking through Harvard Square. Allen bought the magazine, rushed to Bill Gates's Currier House residence, and the two resolved to build a BASIC implementation for the machine. They pitched MITS a demonstration before any interpreter existed, then spent roughly eight weeks, with the help of Monte Davidoff, writing one; when Allen flew to Albuquerque, the software ran, and MITS agreed to distribute it as Altair BASIC. Allen moved to Albuquerque, Gates quit Harvard to join him, and the partnership they incorporated there booked $16,005 of revenue by the end of 1976, a modest figure that nonetheless marked the birth of a company built on selling software as a product.

William Henry Gates III, born in Seattle on October 28, 1955, co-founded Microsoft with his childhood friend Paul Allen in 1975 and became the defining executive of the microcomputer revolution. He ran the company as chief executive for twenty-five years, added the presidency and board chairmanship when Microsoft incorporated in 1981, and became the world's youngest self-made billionaire in 1987 at thirty-one, a year after the public offering began compounding his stake. Forbes ranked him the wealthiest person alive in eighteen of the twenty-four years between 1995 and 2017, and in 1999 he became the first person whose net worth briefly passed one hundred billion dollars. Over time he traded operating control for philanthropic scale, co-chairing the Bill & Melinda Gates Foundation with Melinda French Gates from 2000 until 2024, and Time counted him among the twentieth century's hundred most influential people. He and French Gates jointly received the Presidential Medal of Freedom in 2016.

Apple's 1988 copyright suit against Microsoft and Hewlett-Packard sought to block GUI elements resembling the Lisa and Macintosh systems, and its collapse cleared Windows' path. Apple argued that the look and feel of the Macintosh interface, taken as a whole, was protected, and it listed 189 interface elements it claimed were infringed; the court found that 179 of those had already been licensed to Microsoft in the Windows 1.0 agreement, and that most of the rest were either unoriginal to Apple or the only possible expression of an underlying idea. The district court set a standard of virtual identity for infringement, which the Ninth Circuit almost entirely affirmed in 1994, holding that the similarities sprang from the license or from basic ideas and their obvious expression, and the Supreme Court declined to hear Apple's appeal. Apple's only win covered the trash can and folder icons in Hewlett-Packard's NewWave; a parallel Xerox suit against Apple was dismissed.

Microsoft's graphical ambitions predated the Macintosh's success. Gates wanted a graphical user interface as early as 1981, and the spark came at COMDEX 1982, where he saw VisiCorp's Visi On suite demonstrated for IBM-compatible machines; a year later Microsoft learned Apple's GUI, built partly on Xerox PARC research, was far more advanced, and decided it had to differentiate. In August 1983 Gates recruited Scott McGregor, a key developer of PARC's original windowing system, to lead the Windows team, and the environment made its public debut at Fall COMDEX in November 1983, described as a device driver for MS-DOS 2.0 requiring 192 kilobytes of memory and two floppy drives. The retail version finally shipped on November 20, 1985, two years late, as a tiled-window shell over MS-DOS that reviewers received lukewarmly, criticizing its performance and thin software compatibility, though unlike Apple's closed Lisa it could immediately run existing DOS software.

The IBM contract itself earned Microsoft only a small one-time fee for PC DOS, but the prestige of IBM's adoption transformed the firm, and the licensing structure turned that prestige into an empire. Because Gates had declined to transfer the copyright on the operating system to IBM, believing other makers would clone the PC's hardware, Microsoft kept the right to sell its own derivative, MS-DOS, to anyone. Columbia Data Products successfully cloned the IBM BIOS, Eagle Computer and Compaq followed, and a flood of IBM-compatible machines all needed an operating system that Microsoft was free to license non-exclusively, one deal at a time. Through aggressive marketing to clone makers, Microsoft rose from a small player to one of the industry's major vendors, and by the mid-1980s more than ninety percent of the fifteen million Americans using PCs at work were running its operating system. PC Magazine asked whether Gates was the man behind the machine.

86-DOS began in April 1980, when Seattle Computer Products assigned twenty-four-year-old Tim Paterson to build a substitute for CP/M-86, which Digital Research had not yet finished for the new 8086 processor, so the company could sell its memory boards with a working operating system. The result was a CP/M work-alike for 8086 hardware that Microsoft spotted as the answer to IBM's operating-system problem. In December 1980, Microsoft purchased a non-exclusive license for 86-DOS from Seattle Computer Products for $25,000, enough to begin adapting it while the IBM negotiations proceeded. Then, in July 1981, one month before the IBM PC's release, Microsoft bought all remaining rights to the system outright for an additional $50,000. Those two payments, totaling $75,000, secured the asset that MS-DOS was built on, and Paterson himself joined Microsoft to adapt the code for the PC, a transaction that ranks among the great bargains in the industry's history.

Before Microsoft, there was Traf-O-Data, the 1970s partnership among Gates, Allen, and hardware builder Paul Gilbert. Roadway traffic counts were then recorded mechanically on paper tape, with time and axle counts punched as patterns, and state and local governments paid firms to process them; the two Lakeside students reasoned they could do the work cheaper and faster with a machine built on the newly announced Intel 8008 microprocessor. Neither knew hardware design, so Gilbert became the third partner and built a prototype that read the tape's hole patterns onto computer cards, while Gates used a University of Washington machine to produce the traffic-flow charts. The business achieved only modest success, but it mattered far beyond its revenue: Allen's 8008 emulator, written for Traf-O-Data, became the foundation on which the two simulated the Altair and wrote the BASIC interpreter that launched Microsoft.

The 1986 initial public offering, opening at $21 and closing near $28, created extraordinary wealth inside Microsoft: the subsequent rise of the stock made an estimated four billionaires and twelve thousand millionaires of the company's employees, with Gates's retained 44.9 percent stake anchoring his decades atop the wealth rankings. The company Steve Ballmer inherited as chief executive in 2000 and handed to Satya Nadella on February 4, 2014, kept compounding. Microsoft became the third United States public company to be valued at over one trillion dollars in April 2019, and pandemic-era demand pushed its valuation toward two trillion as cloud computing carried earnings. Both Standard & Poor's and Moody's have awarded the company a AAA credit rating, a distinction its assets and low borrowing costs long supported, and it overtook ExxonMobil in November 2014 to become the second most valuable public company behind Apple.

Paul Gardner Allen, two years older than Gates, met him at Seattle's Lakeside School, which Allen attended from 1965 to 1971, and the two sharpened their programming on the school's Teletype terminals and on University of Washington machines until they were banned from the laboratory in 1971 for abusing their privileges. It was Allen who bought the Popular Electronics issue announcing the Altair 8800 and rushed it to Gates, and Allen who convinced Gates to leave Harvard to build the software company that became Microsoft. Allen named the partnership, negotiated the first MITS demonstration, and wrote the interpreter's make-or-break bootloader on the flight to Albuquerque. His 2011 memoir, Idea Man, fixed his reputation as the technologist and visionary half of the founding duo, the one who saw the personal-computing future first and pulled Gates into it, with the title itself a summary of how Allen understood the partnership's division of labor.

TerraPower, the Bellevue-based nuclear reactor company Gates co-founded and chairs, began with a traveling-wave reactor design and a 2015 agreement with China National Nuclear Corporation to build a 600-megawatt prototype at Xiapu in Fujian province, with commercial plants planned for the late 2020s; the project was abandoned in January 2019 when the Trump administration restricted the necessary technology transfers. The company then won a October 2020 Department of Energy award, between $400 million and $4 billion over five to seven years, under the Advanced Reactor Demonstration Program for its sodium-cooled Natrium design. In June 2021 TerraPower and PacifiCorp, a Berkshire Hathaway Energy subsidiary, announced plans for a joint reactor, and on November 16, 2021, Kemmerer, Wyoming, was selected from four coal-reliant candidate towns. The 345-megawatt project, estimated at four billion dollars with the department covering half and Gates contributing a billion, broke ground in June 2024 and received its construction permit in March 2026, the first ever granted for a non-light-water reactor.

The company's early identity took shape around naming and place. Allen devised Micro-Soft as a portmanteau of microcomputer and software; the hyphen disappeared within a year, and the name Microsoft was registered with the New Mexico Secretary of State on November 26, 1976. Ric Weiland, a high-school collaborator, was the first employee hired. The first international office, ASCII Microsoft in Japan, opened on November 1, 1978, and on January 1, 1979, the company moved from Albuquerque to Bellevue, Washington, because top programmers were hard to recruit to New Mexico; eleven of the thirteen employees posed for a staff photograph just before the relocation. The move put the young firm back in the Seattle orbit where Gates and Allen had grown up, within reach of the talent pool that would power its next decade. Microsoft's BASIC variants were simultaneously becoming the dominant programming language of early home computers, including the Apple II and the Commodore 64.

Gates grew up in Seattle's Sand Point neighborhood, the only son of William Gates Sr., a prominent lawyer, and Mary Maxwell Gates, who sat on the boards of First Interstate BancSystem and United Way of America; his maternal grandfather, J. W. Maxwell, had been a national bank president. Known as Trey within the family, he was small for his age and bullied as a child, and his parents initially steered him toward the law. The household ran on competition, with a reward for winning and a penalty for losing in everything from card games to swimming to the dock. At thirteen he enrolled at Lakeside Prep, where the Mothers' Club spent rummage-sale proceeds on a Teletype terminal and time on a General Electric machine. Gates wrote his first program there, a tic-tac-toe game in BASIC, was excused from math classes to pursue computing, and became fascinated that the machine executed code perfectly every time.

Diagnosed with Stage 1-A Hodgkin lymphoma in 1982, Allen quit day-to-day work at Microsoft in early 1983 while remaining on its board as vice chairman, resigning from the board entirely on November 9, 2000, after which he stayed only as a senior strategy advisor. He and his sister Jody founded Vulcan in 1986 to manage his business and philanthropic affairs, and he built a multi-billion portfolio that included owning the Seattle Seahawks and Portland Trail Blazers and co-owning the Seattle Sounders. He founded the Allen Institutes for Brain Science, Artificial Intelligence, and Cell Science, funded SpaceShipOne's 2004 first crewed private spaceflight, gave more than two billion dollars to education, conservation, and the arts, and located famous warship wrecks. A 2009 non-Hodgkin lymphoma diagnosis preceded his death from septic shock on October 15, 2018, at sixty-five, with an estimated $20.3 billion net worth.

The Albuquerque demonstration became founding legend. On final approach into the airport, Allen realized they had forgotten to write the bootloader that would read the punched paper tape into the Altair's memory, and he finished writing it in 8080 machine language before the plane landed. Only when the tape loaded and the machine displayed a prompt asking for its memory size did they know the interpreter actually ran on Altair hardware. Roberts agreed to distribute the software and hired them to maintain and improve it, with Allen becoming MITS vice president and director of software at $30,000 a year while Gates worked as a contractor titled Software Specialist. The July 22, 1975 contract paid $3,000 at signing plus royalties per copy sold, thirty dollars for the 4K version, thirty-five for 8K, and sixty for the extended edition, capped at $180,000, with MITS holding a ten-year exclusive worldwide license.

The economics behind the letter were unforgiving. MITS sold the Altair 8800 itself at break-even, counting on memory boards, input-output cards, and other add-ons for profit, so software royalties were one of the few clean revenue streams available to the young partnership, and the April 1975 MITS newsletter had already trumpeted Altair BASIC as up and running. The 8K and extended editions carried the higher royalty tiers that unpaid copying erased. The 1975 contract paid Gates and Allen thirty dollars per 4K copy sold against a $180,000 cap, meaning widespread copying struck directly at their income. Microsoft became independent of MITS in late 1976 and kept developing programming-language products for other systems, carrying the paid-software doctrine forward. Looking back, the letter functions as the industry's founding declaration that software is a product with value, not a giveaway that rides along with hardware.

Windows 1.0's commercial defense was legal as much as technical. Apple had agreed to license certain parts of its graphical interface to Microsoft for Windows 1.0, and Microsoft courted hardware makers, with Compaq, Zenith, and DEC supporting the environment while Microsoft encouraged even competitors to write Windows applications without adopting Microsoft's own interface conventions. The operating environment included multitasking, mouse support, and built-in programs such as Calculator, Paint, and Notepad, though its windows could not overlap. Windows 2.0, released December 9, 1987, added overlapping windows and other Macintosh-like features, which Apple treated as exceeding the 1985 license and answered with a copyright suit in 1988. Microsoft supported Windows 1.0 until December 31, 2001, making it the longest-supported version of Windows ever shipped, a quiet monument to how early Gates had placed the graphical bet. The company had begun selling the Microsoft Mouse in May 1983 to give the environment a pointing device.

The Department of Justice, joined by twenty state attorneys general and the District of Columbia, filed suit on May 18, 1998, before Judge Thomas Penfield Jackson of the United States District Court for the District of Columbia, focusing on predatory strategies and barriers to entry. Gates himself never testified at trial; instead his pretrial videotaped deposition became infamous, with a source present calling him evasive and nonresponsive as he sparred with examiner David Boies over the contextual meaning of words like compete, concerned, and we. When excerpts played in court, the judge was seen laughing and shaking his head, and reporting noted that many denials were directly refuted by prosecutors with snippets of emails Gates had sent and received. An Intel vice president quoted a senior Microsoft executive's stated intention to smother Netscape and cut off its air supply by giving away a clone of its flagship browser for free.

The bundling worked. Netscape Navigator dominated browsing in the mid-1990s, but every Windows user received a copy of Internet Explorer without buying anything, and the browser only superseded Netscape once it caught up technologically to support the progressive features of the era, a takeover that began in earnest with version 4.0 in 1997. Microsoft's victory in what became known as the first browser war drove Internet Explorer to a peak of ninety-five percent usage share by 2003, a dominance that invited the regulatory response and, eventually, stagnation. Under a 1997 agreement with Apple, Internet Explorer was also bundled with the Macintosh operating system. The browser's long decline ended with retirement, and its successor Edge, rebuilt on Chromium, did not overtake the old Internet Explorer's standing until November 2019, a two-decade arc from the most distributed software on earth to a museum piece.

In June 2006, Warren Buffett pledged roughly ten million Berkshire Hathaway Class B shares, then valued at $3,071 each before a later fifty-to-one split, to be delivered over multiple years, with the first 500,000-share tranche worth about $1.5 billion. The gift came with three conditions: Bill or Melinda Gates must remain alive and active in the foundation's administration, the foundation must continue to qualify as a charity, and each year it must give away the previous year's Berkshire contribution plus an additional five percent of net assets, effectively converting the donation into a matching grant that doubled giving rather than swelling the endowment. The foundation received five percent of the earmarked shares in 2006 and declining installments each July thereafter, with Buffett adding another two billion dollars of stock in 2018. His cumulative giving to the foundation reached roughly $48 billion before the partnership ended in 2026.

On April 3, 2000, the district court ruled Microsoft an abusive monopoly that had committed monopolization, tying, and blocking of competition in violation of the Sherman Act, and on June 7, 2000, it ordered the company split in two. The victory dissolved on appeal: on June 28, 2001, the D.C. Circuit overturned Judge Jackson's rulings, adopting a drastically altered scope of liability because of the judge's own misconduct, including secret press contacts during the trial, and it vacated the breakup. Microsoft then settled with the Justice Department on November 1, 2001, agreeing to let PC manufacturers adopt non-Microsoft software, and the district court accepted most of the settlement in 2002, with obligations expiring November 12, 2007. Critics on the other side called the result a special antitrust immunity; Gates later said the litigation years contributed to Microsoft losing the mobile operating system race to Android, which he called his biggest mistake.

Steve Ballmer, whom Gates had met at Harvard, joined on June 11, 1980, and would succeed Gates as chief executive from January 2000 until February 2014. On June 25, 1981, Microsoft restructured as a Washington corporation, making Gates president and chairman of the board and Allen executive vice president and vice chairman. The partnership fractured in early 1983, when Allen left after receiving a Hodgkin lymphoma diagnosis, an exit preceded by months of strain over a contentious dispute about Microsoft equity. The two men later repaired the relationship, donated millions together to Lakeside School, and remained friends until Allen's death in October 2018, but the formal business partnership between Microsoft's two founders had effectively ended while the company was still on its way up, leaving Gates with undivided operating control of the firm he would lead as chief executive for another nineteen years.

When the Mothers' Club computer fund ran out, Gates and other Lakeside students chased time on DEC PDP minicomputers, including a PDP-10 run by Computer Center Corporation, which banned Gates, Paul Allen, Ric Weiland, and Kent Evans for a summer after catching them exploiting operating-system bugs to obtain free time. The four responded by forming the Lakeside Programmers Club and offering to find bugs in CCC's software in exchange for terminal hours; Gates went to the company's offices in person and studied the source code of Fortran, Lisp, and machine-language programs until the arrangement ended in 1970. In 1971 a teacher enlisted Gates and Evans to automate Lakeside's class scheduling for computer time and royalties. Evans was killed in a mountain-climbing accident near the end of junior year, a day Gates later ranked among the saddest of his life, and Allen stepped in to finish the system.

The foundation's health bets were sized to move global systems. It underwrote Gavi, the vaccine alliance launched at the 2000 World Economic Forum, with a $750 million pledge covering its first five years and a further $750 million donation on January 25, 2005, supported the creation of the Global Fund to Fight AIDS, Tuberculosis and Malaria with a $100 million pledge in 2002 that grew to more than six billion dollars, and gave $86 million toward polio eradication in 2006, later becoming a core partner of the Global Polio Eradication Initiative. Programs it backed helped cut measles deaths in Africa by ninety percent since 2000, while Gavi and partners immunized more than 760 million children and prevented over thirteen million deaths. The foundation established the Gates Cambridge Scholarships in 2000, launched the Grand Challenges in Global Health research fund in 2003, and pledged $1.6 billion at the June 2020 Global Vaccine Summit, bringing its total Gavi commitments to six billion dollars, the foundation's largest single investment.

IBM approached Microsoft in July 1980 about software for its forthcoming personal computer, a connection eased by Gates's mother's service on a United Way board alongside IBM chief executive John Opel. IBM initially asked Microsoft to write the BASIC interpreter and, when the subject of an operating system arose, Gates referred the company to Digital Research, maker of the dominant CP/M system; those negotiations failed. When IBM's Jack Sams reported the impasse, Gates and Allen proposed 86-DOS, a CP/M-like system Tim Paterson had built at Seattle Computer Products. Microsoft first licensed and then fully acquired the system, hired Paterson to adapt it for the IBM PC, and delivered it as PC DOS for a one-time fee of $50,000. Gates deliberately did not transfer the copyright to IBM, betting other manufacturers would clone the hardware; they did, and MS-DOS became the industry's de facto standard.

Leadership of the foundation professionalized across its first quarter century: Patty Stonesifer served as the first chief executive until 2008, Jeff Raikes succeeded her, Susan Desmond-Hellmann took over in 2014, and Mark Suzman replaced her in February 2020. The founders' 2021 divorce forced governance changes, including a two-year trial arrangement after which either could exit; Melinda French Gates resigned as co-chair on May 13, 2024, effective that June, and in January 2025 the foundation was renamed the Gates Foundation with Bill Gates as sole chair. Warren Buffett resigned as trustee in June 2021 and clarified in June 2024 that the foundation would receive nothing further from his estate. The institution held $91 billion in assets at the end of 2025, had committed more than two billion dollars to pandemic response, and had co-hosted the 2019 Event 201 pandemic exercise with the World Economic Forum.

A national merit scholar who scored 1590 out of 1600 on the SAT, Gates enrolled at Harvard in the autumn of 1973, taking Math 55 and graduate-level computer science courses without ever settling on a concentration. There he met fellow student Steve Ballmer, the future Microsoft chief executive who stayed to graduate magna cum laude while Gates left after two years. In a combinatorics class taught by Professor Harry Lewis, Gates devised an algorithm for pancake sorting that held the record as the fastest solution for more than thirty years, with its eventual successor only two percent faster, and the work was formalized and published with Harvard computer scientist Christos Papadimitriou. During the summer of 1974 Gates joined Allen at Honeywell, keeping the partnership alive until the Altair 8800 created the opportunity that pulled him out of Cambridge for good.

The January 1975 issue of Popular Electronics, demonstrating the MITS Altair 8800 built on the Intel 8080, convinced Gates and Allen that the moment had arrived to start a software company, and Gates dropped out of Harvard that same year. His parents were supportive once they saw how badly he wanted it, and he framed the decision conservatively: he remained officially on leave, so that if the venture failed he could always return to school. He never went back to complete his degree. Instead he took a leave of absence in November 1975 to work with Allen at MITS in Albuquerque, where their new partnership, named Micro-Soft as a blend of microcomputer and software, opened its first office. The trade name Microsoft was registered with the Secretary of State of New Mexico on November 26, 1976, dropping the hyphen within a year.

Through the mid-1980s Microsoft scaled from scrappy to dominant. SoftLetter reported the company, with an estimated $55 million in 1983 sales, as the world's second-largest microcomputer software company; InfoWorld called it the industry's most influential firm, with some insiders saying it aimed to be the IBM of software, and more than ninety percent of the fifteen million Americans using a PC at work ran MS-DOS. On February 16, 1986, Microsoft moved to a corporate campus in Redmond, and on March 13, 1986, it went public on the Nasdaq at $21.00 per share, raising $61 million as the price ended the day at $28.00. By 1987 it was the largest personal-computer software producer, having passed Lotus, and its July 1987 purchase of Forethought, the developer of PowerPoint, marked its first major acquisition. Cytation, picked up in January 1986, had already formed the company's CD-ROM division months before the offering.

The foundation was designed to die. In October 2006 it was split into a trust that manages the endowment and an operating foundation that makes grants, with the announcement that all resources would be spent within fifty years of Bill's and Melinda's deaths, a deadline later tightened to twenty years in contrast to the perpetual life of most large foundations. In May 2025, Gates went further, announcing that the foundation would cease operations on December 31, 2045. The spend-down logic is administrative as much as philosophical: a fixed horizon lowers administrative costs over the institution's life and prevents the drift into token grantmaking that consumes perpetual endowments. Buffett's own stipulation that proceeds from shares he still owns at death be deployed within ten years of his estate's settlement reinforced the same conviction that philanthropic capital should be spent, not preserved.

In Microsoft's first five years Gates personally reviewed, and often rewrote, every line of code the company produced, before growing into a manager and then an executive role. He was never officially on a development team after his work on the TRS-80 Model 100, yet he wrote code that shipped in company products as late as 1989, keeping a programmer's authority inside a fast-scaling organization, an era of the company's history later captured in the Microsoft Press interview collection Programmers at Work. When Microsoft Excel was announced in 1985, the technology columnist Jerry Pournelle observed that Gates liked the program not primarily for the money it would make but because it was, in his judgment, a neat hack. The same intensity drew criticism in the late 1990s, when his business tactics were widely considered anti-competitive, an opinion subsequently upheld in multiple court rulings that reshaped how the company could behave toward partners and rivals.

Gates committed Microsoft to the graphical interface years before it paid off. Computerworld noted in 1987 that he had pushed Windows almost fanatically for years while much of industry treated it as a joke, and a Microsoft manager later recalled that betting the company on it was an enormous wager. Windows 3.0, launched May 22, 1990, sold more than 100,000 copies in two weeks and pulled resources away from OS/2, the operating system Microsoft had been co-developing with IBM since an August 1986 agreement; in a May 16, 1991 internal memo, Gates declared the OS/2 partnership over and redirected the company to Windows and the Windows NT kernel, a switch developers who had backed OS/2 called the head-fake. By 1993 Windows was the world's most widely used graphical operating system, vindicating a decade of insistence. Windows 3.1 followed in March 1992 and sold more than three million copies in its first two months on the market.

The Internet initially caught Microsoft flat-footed, and Gates's response became a corporate legend. Windows 95 shipped on August 24, 1995 without a web browser, and the web's rise surprised the company, which then licensed Spyglass technology to build Internet Explorer rather than give it away for nothing. On May 26, 1995, Gates sent executives the Internet Tidal Wave memorandum, describing Netscape as a new competitor born on the Internet, admitting Microsoft had failed to grasp the Internet's importance, and assigning it the company's highest level of importance from then on. More than a million copies of Windows 95 sold in the first four days, and Microsoft launched MSN the same summer as a direct challenge to AOL. In 1998 Gates appointed Ballmer president while remaining chairman and chief executive himself, dividing leadership at the exact moment the antitrust trial began.

In June 2006 Gates announced he would transition out of his day-to-day Microsoft role to concentrate on philanthropy, splitting his responsibilities between Ray Ozzie, who took over management, and Craig Mundie, who took long-term product strategy; the two-year handover was completed on June 27, 2008. He stepped down as chairman in February 2014, handing the board chair to John W. Thompson and becoming a technology adviser to the newly appointed chief executive Satya Nadella, a position he has retained. In March 2020 Microsoft announced Gates would leave his board seats at both Microsoft and Berkshire Hathaway to devote himself to climate change, global health and development, and education. The Wall Street Journal later reported that his departure came before the board concluded an external law firm's probe, begun in late 2019, into an alleged inappropriate relationship with a Microsoft employee, leaving his four-decade operating role at the company fully behind.

When Microsoft went public in 1986, Gates retained 44.9 percent of the company, and the following year Forbes listed him as a billionaire with $1.25 billion, the youngest self-made billionaire in the world at thirty-one. He held the top spot on the Forbes 400 from 1993 through 2007 and again later, and Jeff Bezos finally displaced him as the world's richest person in October 2017, with Gates briefly regaining the position in November 2019 after a surge in Microsoft shares. He has described himself as having paid more tax than any individual, over six billion dollars, gladly, and advocates higher taxes particularly for the wealthy. His fortune also funded an unusual collector's streak, including the Codex Leicester, Leonardo da Vinci's scientific writings, bought at auction in 1994 for $30.8 million, and a Medina estate nicknamed Xanadu 2.0. He has since announced his intention to give away virtually all of his fortune over time and move off the world's-richest lists.

Gates's public image has swung across eras: from the hard-driving executive once caricatured as a tyrannical technocrat, he was remade in the 2000s into a celebrated techno-philanthropist, magazine-cover material whose opinions on global health and climate carried weight. The 2021 announcement of his divorce from Melinda French Gates brought a harsher turn, as coverage surfaced romantic pursuits of women who worked for him, a long-term extramarital affair, and a friendship with convicted sex offender Jeffrey Epstein, and his handling of pandemic-era controversies deepened the shift. His investment vehicle Cascade Investment made him the largest private owner of farmland in the United States, with roughly 242,000 acres across nineteen states, the single largest shareholder of Canadian National Railway, and a 16 percent holder of AutoNation. He flew commercial coach class on business trips until 1997, the year he finally bought his first private jet.

Gates has also built a substantial body of writing. The Road Ahead, published in November 1995 with Nathan Myhrvold and Peter Rinearson, summarized the personal-computing revolution and forecast a world reshaped by a global information superhighway. Business @ the Speed of Thought, written with Collins Hemingway and published in 1999, argued that digital infrastructure and information networks could give companies a competitive edge. Two decades later his subject matter turned planetary: How to Avoid a Climate Disaster, published in 2021, distilled more than a decade of studying climate change and investing in energy innovation, and How to Prevent the Next Pandemic, published in 2022, proposed a Global Epidemic Response and Mobilization team of full-time experts under the World Health Organization, with about a billion dollars of annual funding. In February 2025 he published Source Code: My Beginnings, the first of three planned memoirs.

Gates spent years warning that the world was unprepared for a pandemic, telling a TED conference audience in March 2015 that the next global outbreak would catch governments flat-footed, a warning that preceded the arrival of COVID-19 in late 2019. During the crisis, media outlets treated him as an authority despite his lack of public office or medical training, and his foundation created the COVID-19 Therapeutics Accelerator in 2020 to speed the development and evaluation of new and repurposed treatments. He described frequent conversations with Anthony Fauci on vaccines and medical innovation. In April 2021 he drew criticism for arguing that pharmaceutical companies should retain vaccine patents and for opposing the TRIPS waiver, contending that safety protocols and the difficulty of transferring production, not intellectual property, were the real constraints on supply; his foundation had encouraged Oxford University to partner with a major manufacturer rather than give away its vaccine, and Oxford chose AstraZeneca.

In 2025 Gates made two decisions that define his philanthropy's endgame: he will donate virtually all of his remaining wealth, about $200 billion, over the following two decades, and the foundation will close its doors at the end of 2045. In his own telling of the story, he understood from the beginning that the foundation would not be permanent, because philanthropy works best when it is time-limited and aimed squarely at the needs that matter most. The final chapter concentrates the institution on three goals: no mother, child, or baby dying of a preventable cause, a generation growing up without deadly infectious diseases, and hundreds of millions of people escaping poverty. Across its first twenty-five years the foundation invested more than $102.3 billion in global health and development, American education, and economic mobility, with teams and partners in over 140 countries, and child mortality has been cut in half since 2000.

In his 2021 pledge letter, Gates grounded his philanthropy in childhood ritual: his parents gave him a weekly allowance he could spend freely, but at the dinner table they asked how much of it he planned to give to the Salvation Army at Christmas. The message was that if you are in a position to help somebody, you should do it, and his parents taught generosity through how they used their time and resources. When the time came to decide what to do with his Microsoft wealth, he followed their example, resolving that the vast majority would go toward helping as many people as possible, mostly through the foundation. He measures the results in lives: more than eight hundred million children supported with vaccination, and American schools helped to keep more kids on track to graduation. His giving beyond the foundation has grown in climate mitigation and Alzheimer's research, and he invokes his father's maxim that there is no problem bigger than they are.

The foundation's origin story, as Gates tells it, begins with his parents and a newspaper article. The core belief that every life has equal value came from lessons his mother and father taught early, and as Microsoft wealth grew in the late 1990s, he and Melinda began looking for ways to give back, starting with expanding technology access in American public libraries. Then he read an article reporting that millions of children in poor countries were dying annually of diseases that rich nations had long since learned to prevent, and he sent it to his father with a note asking whether they could do something about it. That moment redirected his life. He began meeting scientists, health workers, and community leaders to learn where philanthropy could matter, and the foundation born in 2000 co-founded Gavi with a $750 million pledge and helped create the Global Fund, with Warren Buffett's extraordinary 2006 pledge of more than $30 billion enabling bigger, longer bets.

The original 2010 pledge letter that Gates signed with Melinda opened with rotavirus, a highly preventable disease killing half a million children every year while airplane crashes dominated front pages and most people could not name the killer. The couple committed the vast majority of their assets to the foundation to stop such deaths and dismantle barriers to health and education, animated by the principle that all lives have equal value. Vaccines, they wrote, are miracles, tiny vessels of hope, and the letter pressed for both wider delivery of existing vaccines and the development of new ones, alongside a parallel push in American education. The pledge itself grew out of gatherings with other givers, comparing what had worked in philanthropy and what had not, and the letter closes on inheritance values passed from their parents: work hard, show respect, keep a sense of humor, and use whatever talent or treasure life grants as wisely as possible.

The foundation's own timeline records an unbroken escalation. The William H. Gates Foundation formed in 1994 to fund scientific research, global health, and local causes; the Gates Library Foundation followed in 1997, helping United States public libraries offer free internet access before going global and reaching more than fifty countries and 280 million lives. In 1999 the epidemiologist William Foege joined as senior advisor to craft the global health strategy, and the Gates Millennium Scholars program began, ultimately benefiting more than twenty thousand low-income students of color. The merged Bill & Melinda Gates Foundation launched in 2000 alongside Gavi's creation at the World Economic Forum and the Sound Families homeless-housing effort in Puget Sound. In 2002 came a $100 million founding pledge to the Global Fund, in 2003 the Grand Challenges program and an India office whose HIV prevention work halved infection rates within a decade, and in 2006 the Alliance for a Green Revolution in Africa, which has since reached more than twenty million smallholder farmers.

The institution's later history pairs programmatic ambition with planned obsolescence. The Gates Notes-era initiatives piled up: the 2011 challenge to reinvent the toilet, the 2012 London family-planning summit that set a goal of reaching 120 million more women with contraceptives, the London Declaration on neglected tropical diseases the same year, India and Southeast Asia certified polio-free in 2014, and $1.75 billion committed to COVID-19 response in 2020, the year Africa was certified free of wild poliovirus. Governance followed: Bill Gates Sr., the foundation's north star and strategic guide, died in September 2020; Warren Buffett stepped down as trustee in 2021 after fifteen years, having contributed $43 billion to date; an independent governing board was appointed in 2022; Melinda French Gates left in 2024; and in May 2025 the $200 billion, 2045 sunset was announced. Gates insists the goal is not innovation itself but the impact it makes possible.