“It’s funny in a way”, says Bill Gates, relaxing in an armchair in his office. “When I was young, I didn’t know any old people. When we did the microprocessor revolution, there was nobody old, nobody. It’s weird how old this industry has become.” The Microsoft cofounder and I, a couple of fiftysomething codgers, are following up on an interview I had with a tousle-headed Gates more than a quarter century ago. I was trying to capture what I thought was the red-hot core of the then-burgeoning computer revolution — the scarily obsessive, absurdly brainy, and endlessly inventive people known as hackers. Back then, Gates had just pulled off a deal to supply his DOS operating system to IBM. His name was not yet a household word; even Word was not yet a household word. I would interview Gates many times over the years, but that first conversation was special. I saw his passion for computers as a matter of historic import. Gates himself saw my reverence as an intriguing novelty. But by then I was convinced that I was documenting a movement that would affect everybody.