Before he became famous for leaking the Pentagon Papers, Ellsberg was a bright analyst at the RAND Corporation who worked on some of the most perplexing problems in U.S. national security. This candid and chilling memoir describes how he came to recognize that the U.S. military’s approach to preparing for nuclear war was terrifyingly casual. If war came, the United States was ready to obliterate not only the Soviet Union but also China, as a matter of course—a plan that would have immediately produced 275 million fatalities and then led to another 50 million, owing to the effects of radiation. And those numbers do not even include the lives that would have been lost by the United States and its allies. Ellsberg was appalled, but he understood the logic of deterrence and the policy challenges that had allowed such an approach to develop. This gives his account credibility and poignancy: at one point, he drafts an alternative war plan that would still have horrific consequences—just not as awful as the one it would replace. His experiences have led Ellsberg to argue that however much he might like to see nuclear weapons abolished, the first step in addressing the danger must be to make them harder to use.