They were men of the system: supremely talented, among the most important theoretical physicists in the twentieth century, and central to the development of nuclear weapons in the Soviet Union. Their critical roles protected them whenever they strayed. Lev Landau, one of the most brilliant scientists in the set, doomed himself to a year in the secret police’s prisons by signing a pamphlet that called Stalin a fascist. But his fate would have been far worse if not for the fact that his superior, Pyotr Kapitsa, intervened on his behalf and persuaded the authorities to release him. Kapitsa headed the critical Institute of Physical Problems, which Stalin had created specifically for Kapitsa in 1934, after refusing to let the physicist return to the United Kingdom, where, since 1921, he had flourished as a researcher. Hargittai, a distinguished Hungarian chemist, relates 12 compact biographies of scientific giants such as Igor Tamm, Andrei Sakharov, Nikolai Semenov, and Yuli Khariton, some of whom he knew personally. His mosaic of a book conveys well the triumphs, tensions, and twists of fortune in this rarified corner of Soviet life.