But Microsoft's other cofounder, Paul Allen, has only become famous (outside of Seattle) since he published his memoirs in 2011.
He, too, is plenty wealthy, the No. 55 richest man in the world, worth $16 billion.
With his money, he's invested in a lot of tech companies, real estate, and art. But he's also led an over-the-top life filled with rock and roll parties, collections, yachts, and sports teams.