Bill Gates

After years of tinkering with computers, Gates dropped out of Harvard at age 19 to form Microsoft Corp. with Paul Allen. The firm's initial focus was on porting operating systems (the basic instructions that tell the computer how to turn on, recognize peripherals, etc.) from one computer type to another. They soon developed their own version of DOS, which competed directly with IBM's version. Eventually the firm's Windows operating system would appear on some 80 percent of the world's computers, its popularity bolstered by Microsoft applications (software such as word processors, spreadsheets, databases, games and other programs designed to automate everyday tasks for business and the home) built to run on their operating system. Microsoft is the world's largest producer of software for microcomputers and Bill Gates is today one of the world's richest men.

In recent years, Gates and his wife Melinda have established the Bill and Melinda Gates Foundation to help fight poverty and improve health care and education around the world. With a $29 billion endowment, it is the world's largest charity. The foundation has donated about $5 billion to developing nations to fight AIDS and malaria, two of its major areas of concentration. Its vaccination programs in poor countries are credited with saving at least 700,000 lives. Another emphasis of the foundation is on education; it sponsors the largest scholarship fund in history.