Over lunch in his suburban Seattle office, Nathan Myhrvold says he's looking forward to an afternoon meeting with a group of nuclear-fusion experts. "It's a real bitch," he remarks of the problem scientists have had controlling hydrogen reactions and achieving the ultimate dream of cheap, safe, renewable energy. Such thorny technological conundrums fascinate the bearded, cherubic veteran of Microsoft's inner sanctum. Like dozens of other domains, he says, fusion is ripe for a revolution. "There needs to be a big new idea," Myhrvold muses.

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