Surely, Andrei Sakharov will be regarded as one of twentieth-century Russia's historic figures. His scientific achievements, including his role in the development of Soviet nuclear weapons, along with his courage and prominence as a political dissident, guarantee that. Bergman, however, introduces a figure who transcends Russian history. Sakharov's faith in reason, originally limited to the sphere of nuclear weapons, gradually acquired a moral sensibility stirred by the ethical implications of testing these weapons in the atmosphere, a step that led to a far more profound concern with the whole sphere of human rights. Bergman opens Sakharov's mind to the reader and illustrates how Sakharov bonded reason with ethics and applied ideas not only to an astonishing range of technical scientific subjects but also, ultimately, to matters of human freedom and world peace. This makes Sakharov of greater philosophical interest, and the book, an excellent companion to Richard Lourie's earlier sterling biography.