In December 2016, the Bulletin of Atomic Scientists moved their iconic “Doomsday Clock” thirty seconds forward to two and a half minutes to midnight, the latest it has been set since 1952, the year of the first United States hydrogen bomb test. But a group of scientists—geologists, engineers, and physicists—has been fighting to turn back the clock. Since the dawn of the Cold War, they have advocated a halt to nuclear testing, their work culminating in the Comprehensive Test Ban Treaty, which still awaits ratification from China, Iran, North Korea—and the United States. The backbone of the treaty is every nation’s ability to independently monitor the nuclear activity of the others. The noted seismologist Lynn R. Sykes, one of the central figures in the development of the science and technology used in monitoring, has dedicated his career to halting nuclear testing. In Silencing the Bomb, he tells the inside story behind scientists’ quest for disarmament.