Even by physicists’ standards, Dyson’s thinking was strikingly unconstrained by the here and now. One moment, he was delving into the esoterica of quantum theory, and, the next, he was speculating about the logistics of alien civilizations. In the nineteen-fifties, he led the team developing a new type of nuclear reactor, which included several novel safety features; soon after, he was designing an interstellar spacecraft propelled by nuclear bombs. – The New Yorker