Robert Oppenheimer never really thought about the ethics of the atomic bomb until the successful test of a plutonium device at Alamogordo, New Mexico, in July 1945. Then, one of the most highly educated men of the 20th century felt an inrush of ethical anguish and spent the rest of his life trying to come to terms with what he, what America, and what humankind had done. Historian Clay Jenkinson examines the gated world of Los Alamos, the race to build the bomb, Oppenheimer’s ethical quandary about nuclear warfare—and the price he paid for it.