In the last decades of the 20th century, a revolution in information technology transformed commerce and consciousness, just as the printing press transformed civilization 500 years before. These advances in computer technology and communications would have remained the province of professional scientists and mega-business if not for the introduction of the personal computer, and no person played a greater role in bringing the computer into homes and offices all over the world than William H. Gates, III. Bill Gates was a teenage computer whiz when he dropped out of Harvard to start his own company, Microsoft. Through a brilliant combination of technical prowess and business insight, Gates made Microsoft the indispensable supplier of operating systems and office software to computer users around the world. If you use a computer to write a letter, compose an email or visit a website, chances are you're using Microsoft software. Microsoft's uncontested dominance of the personal computer software market made Bill Gates the richest man in the world for many years. He has used his personal wealth to attack the most intractable global problems of disease and poverty through the Bill and Melinda Gates Foundation. William H. Gates III was born in Seattle, Washington, on October 28, 1955, the second of three children, in between an older and a younger sister. His father was a successful attorney, and it was expected that young Bill would follow in his father's footsteps. He was a notably gifted student who did well in all subjects but showed a special aptitude for mathematics. When he was 13, his parents believed he was not being challenged in his public school and enrolled him in the private and highly demanding Lakeside School. The school acquired a computer terminal, and young Bill Gates was immediately fascinated. He and a small group of friends, including his future business partner Paul Allen, took every opportunity to explore the possibilities of the new technology, teaching themselves the basics of computer programming. Soon Gates and his friends were working part-time and summers, writing computer programs for large businesses around the Seattle area. Although they were all precociously gifted programmers, it became clear that Gates had a unique talent for business as well, and he quickly emerged as the leader of the group. Gates and Paul Allen closely followed events in the computer industry and foresaw that the development of microprocessors would lead to the creation of compact, affordable personal computers that would someday supplant the bulky mainframe systems used in business and industry. The January 1975 issue of Popular Electronics featured the new Altair 8800 and alerted Bill Gates and Paul Allen that the era of the personal computer was beginning. Meanwhile, Gates continued to excel in his studies and followed his parents' wishes by going to Harvard. Paul Allen soon moved to Boston to work for Honeywell and continue their collaboration. The pair were galvanized by the Altair 8800, an inexpensive microcomputer produced by MITS in Albuquerque, New Mexico. Gates and Allen saw this as the beginning of a new industry. No one had yet developed software for the Altair, and the young programmers adapted the computer language BASIC to run on the new device, securing a software development contract with MITS. Gates left Harvard at the beginning of his junior year to move to New Mexico at the end of 1975 to produce software for MITS. In 1976, they started their own company, Microsoft. After MITS was sold, Gates moved Microsoft to Bellevue, Washington, near his hometown of Seattle. When IBM decided to move into manufacturing personal computers in 1980, it turned to Gates and Microsoft to produce an operating system. Gates bought an existing program, QDOS, and adapted it to IBM hardware, naming it Microsoft Disk Operating System (MS-DOS). In his agreement with IBM, Gates retained the right to license MS-DOS to other hardware manufacturers. When the IBM PC succeeded, other manufacturers rushed to create DOS-based compatible PCs, making Microsoft's operating system the universal standard. In 1985, Microsoft introduced Windows, a DOS-based graphical interface. Within a few years, Microsoft office applications became category leaders: Microsoft Word, Excel, PowerPoint, and Internet Explorer. In 1989, Gates founded Corbis, a digital image licensing company. He also served as a director of Berkshire Hathaway and created Cascade Investments LLC. By 1995, Bill Gates became the world's richest man. In 1994, Bill Gates married Melinda French; they have three children. In 2000, they founded the Bill and Melinda Gates Foundation, dedicating tens of billions of dollars toward combating global poverty and disease, expanding educational opportunities, and funding vaccine development. That same year, Gates stepped down as CEO of Microsoft, and in 2008 left day-to-day operations to focus full-time on philanthropy. In 2016, Bill and Melinda Gates received the Presidential Medal of Freedom. Gates has authored works including 'How to Avoid a Climate Disaster' (2021), 'How to Prevent the Next Pandemic' (2022), and 'Source Code: My Beginnings' (2025). In August 2026, he published an essay highlighting the risks of artificial intelligence to human employment and biosecurity, advocating for human-reserved jobs, AI taxation, and international oversight. Bill Gates reflects on dropping out of Harvard in his junior year to start Microsoft: 'Microsoft was the first software company where we wrote software for personal computers. And we believed that we could hire the best engineers. There was an unbelievable amount of software to be written, and we could do it well and we could do it on a global basis. The original customer base was the hardware manufacturers... We knew in the long run we wanted to sell software directly to users, but we actually didn't get around to that until 1980.' Regarding the vision of personal computing, Gates explains: 'Paul Allen and I had used that phrase even before we wrote the BASIC for Microsoft. We actually talked about it in an article in — I think 1977 was the first time it appears in print — where we say, "a computer on every desk and in every home... running Microsoft software." It's very hard to recall how crazy and wild that was... At the time, you have people who are very smart saying, "Why would somebody need a computer?"' Gates discusses early contracts with Apple, Commodore, Radio Shack, and Atari: 'Microsoft did the software for all the personal computers that came out... our BASIC was running on every single machine. We didn't mind doing low priced contracts at the time, because we always knew that there would be new versions and more software that we would do... We always were able to say, "Hey, you would have spent a half a million developing that yourself. We'll license it to you for an inexpensive price."' On copyright and software licensing: 'The MITS Altair people agreed to pay us a royalty for each copy that was sold... if they just copied the program — which was at the time on paper tape — we didn't get paid. There was a lot of this going on, and the amount of piracy was going to determine whether Microsoft could hire more people or not. So I wrote "An Open Letter to Hobbyists," that said, "By the way, this is copyrighted material, and the more we sell, the more software we'll be able to write."' On creating the IBM operating system: 'When IBM saw that we had written the software for all the personal computers, they came to us, sought our advice on the design... another company called Digital Research had done that work for the 8-bit machines... but IBM was getting frustrated because Digital Research wouldn't sign even the non-disclosure agreement. Paul and a key person named Kazi Konishi and I said, "No, no, no, we should just do that ourselves." Because of the quick timing, we licensed the original code from another company and turned that into MS-DOS... In the IBM initial deal, it was a flat fee deal that had restrictions preventing IBM from selling to other hardware makers. So if people did IBM PC compatible machines, we would get the revenue by doing business directly with those people.' Gates recalls reading science fiction, biographies, and classics like 'The Catcher in the Rye' and 'A Separate Peace'. He details how Lakeside School acquired a teletype terminal running BASIC funded by the Lakeside Mother's Club rummage sale, forming the Lakeside Programming Group with Paul Allen, Kent Evans, and Rick, writing school scheduling software, working for C Cubed, and writing grid control software for Bonneville Power via TRW at age 16. Discussing the Gates Foundation: 'Capitalism is this unbelievable open system that if you combine it with good infrastructure, good education, the creativity that we find for people who have had those chances is always going to surprise us... We need new vaccines, we need cheap vaccines, we need vaccines that are easy to deliver, even in the poorest places... This connects to my experience at Microsoft of finding great scientists, making sure they understand the problems that are important, getting them focused on those things, having milestones, and making sure they get proper backing. On the discovery side there's been a deep under-investment, and the Foundation is taking the lead.'