As the head of the theory group at Los Alamos, Hans A. Bethe played a central role in the dawn of the Nuclear Age. In the 50 years since, he has played an equally central role in the debate over the use and control of this new power. This volume collects together Bethe's best essays on the bomb, arms control, nuclear power and astrophysics. It also includes his reflections on science and morality and his comments on five fellow physicists. Of interest to physicists, particularly those working in nuclear physics and astrophysics, historians and philosophers of science, science policy makers, environmentalists, those concerned with disarmament and the role of science in society, and general science readers.