A novel in three movements about the minds that built the modern world and could not control what they made. The long central section belongs to John von Neumann, the Hungarian polymath whose intelligence unnerved everyone who encountered it, and who in a single life invented game theory, designed the architecture underlying nearly every computer since, contributed decisively to the Manhattan Project, and sketched the foundations of artificial life and self-replicating machines. Benjamin Labatut tells von Neumann's story polyphonically, through the voices of his wives, colleagues, and rivals, including Eugene Wigner, Richard Feynman, and Oskar Morgenstern, so that the man himself remains a brilliant absence at the center. Around this Labatut builds a frame: the book opens with the Austrian physicist Paul Ehrenfest, who despaired as science turned tyrannical and killed his disabled son and himself, and closes a century later with the 2016 matches between Lee Sedol and AlphaGo, where a machine plays a move no human would have considered and the Go world's understanding of its own game quietly collapses. As in When We Cease to Understand the World, Labatut works in the unstable zone between documented fact and invention, and readers should not take the dialogue as reportage. What the method delivers is an argument about rationality itself, about the way pure intellect, pursued past a certain point, generates forces that reason cannot afterward govern.