William H. Gates, III

Age: 51

WHAT HE DOES
Bill Gates III is the co-founder and chairman of software giant Microsoft. These days, he’s mainly a philanthropist, the force behind the largest charitable foundation in the world.

WHAT HE’S KNOWN FOR
With his brown hair and trademark glasses, Gates is an icon of the personal-computer revolution, a visionary entrepreneur who left Harvard to start Microsoft with his childhood friend Paul Allen and went on to make billions.

Gates is not just rich; he’s the richest man on earth, with an estimated net worth of about $53 billion, according to Forbes. He pals around with celebrity investor Warren Buffett and has poured tens of billions into his charity, the Bill and Melinda Gates Foundation, named for him and his wife.

Gates is also one of the most recognizable business leaders in the world, and his nerdiness and wealth have inspired Saturday Night Live parodies, movie characters (including Tim Robbins’ C.E.O. in the 2001 flop Antitrust), and public pranks. During a 1998 trip to Belgium, for instance, Gates was smacked in the face with a cream pie as he entered a government building. He didn’t laugh.

Famous for his temper and cutthroat instincts, Gates has aggressively pushed Microsoft’s product strategy since the 1970s and has served at various times as chairman, president, C.E.O., and chief software architect. In the process, Gates created a monopoly out of Microsoft’s Windows operating system, using the ubiquitous platform to shut out competitors.

During Microsoft’s landmark antitrust trial in the late ’90s, United States District Judge Thomas Jackson viewed Gates as uncooperative and evasive, prompting him to accuse Gates of having a “Napoleonic concept of himself and his company, an arrogance that derives from power and unalloyed success.”

Gates has missed a few tricks, however. He’s been criticized for coming late to the internet and for holding Microsoft’s focus to packaged software while Google cornered the search market and Apple captured a large share of the digital-music business.

It’s possible that, in the end, Gates will be better known for his philanthropy than for creating the most successful company in the world. He pledged $16 billion to start his foundation in 1999 and has been pitching improvements in health care and actions to eliminate poverty in Africa and other developing areas ever since, appearing regularly in snapshots holding underfed, undereducated children from the third world. In 2005, Bill and Melinda Gates, along with humanitarian rocker Bono, were named Time magazine’s Persons of the Year.

WHERE HE’S FROM
Gates grew up in Seattle. He went to Harvard in 1973, where, before dropping out during his junior year, he lived down the hall from Steve Ballmer, Microsoft’s current C.E.O. Gates married former Microsoft executive Melinda French in 1994 and has three children.

WHERE HE’S GOING
With Microsoft squarely under the leadership of Ballmer, Gates is turning his attention to his legacy. He plans to step down as Microsoft’s chairman in 2008 to focus on his foundation, which in 2006 received a pledge of more than $30 billion in Berkshire Hathaway stock from Warren Buffett. —Clancy Nolan