Venture capitalist
Age: 42
The author of two canonical books on computer science, Graham made millions selling an e-commerce business to Yahoo in the 1990s. Now he's turning his methodical mind to the business of funding startups, and clever entrepreneurs are benefitting from his scientific patronage. Loopt, Reddit and Justin.tv are some of the hatchlings coming out of Graham's Y Combinator, which aims to pick startups and nurture them with mentorship as well as money. Age: 42
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