Everyone knows about Bill Gates, the boy-wonder founder of Microsoft and the planet’s richest citizen. Although less well known, Paul Allen helped make Gates’s good fortunes possible, and he's certainly worth study for his mistakes just as much as his many successes. Enter former Industry Standard reporter Laura Rich, who does little to demystify Allen the man, but paints a useful portrait all the same. Rich takes readers through Allen’s career as an early Gates ally, a technically savvy man who first saw the possibilities of DOS, the operating system that drove a big chunk of the personal computer market, and launched several other software enterprises. Although he left Microsoft owing to illness in 1983 (according to Rich, Gates has behaved badly toward him ever since), Allen is still a major shareholder and has amassed a personal fortune that dwarfs the GNPs of whole nations. As Rich observes, Allen has put this money to good use as "technology’s archangel," but has also managed to lose staggering sums in misguided ventures--some too far ahead of their time, some just plain wacky.