As a former colleague of Oppenheimer's, Jeremy Bernstein has written a biographical profile that is both personal and historical, bringing the reader close to the life and workings of an extraordinary and controversial man. Without Oppenheimer's totally remarkable leadership at Los Alamos, the atomic bomb would not have happened, and World War II would have ended very differently. Bernstein, combining the grace of a New Yorker writer with the insight of a theoretical physicist, draws a fine and fascinating portrait. —Arthur Schlesinger, Jr.