Bill Gates
Net Worth: $58 billion
Dropped out of Harvard University
Harvard dropout and Microsoft visionary no longer the world’s richest man. He was passed by Warren Buffett and Carlos "Slim" Helu in Forbes’ most recent list of the world’s billionaires. His foundation, the Bill & Melinda Gates Foundation, has $38.7 billion in assets, donates to causes aimed at bringing financial tools to the poor, speeding up the development of vaccines (for AIDS, malaria, tuberculosis), bettering America’s lagging high schools. Sells 20 million Microsoft shares every quarter, proceeds going to private investment vehicle Cascade; more than half of net worth now outside Microsoft.

Li Ka-shing
Net Worth: $26.5 billion
Dropped out of school at 12
Once a poor immigrant, Li got his start selling plastic flowers in Hong Kong in the 1950s. Now Hong Kong’s richest person. He is the world’s largest operator of container terminals, world’s largest health and beauty retailer, a major supplier of electricity to Hong Kong and a real estate developer. He has announced plans to donate one-third of wealth over time. Eldest son Victor helps him run his massive empire; son Richard struck out on his own in early 1990s and is a billionaire of his own right.

Sheldon Adelson
Net Worth: $26 billion
Dropped out of City College of New York
Cab driver’s son borrowed $200 from uncle to sell newspapers at age 12. Studied voice in teens, later dropped out of City College in New York City to become court reporter. Made first fortune in trade shows. Created computer industry’s marquee event, Comdex. Then Vegas: bought Sands Hotel & Casino for $128 million, demolished it to build the $1.5 billion all-suites Venetian Resort Hotel Casino and the 1.2-million-square-foot Sands Convention Center. Changed the way casinos do business by enticing conventioneers to Sin City mid-week, taking emphasis off gambling.