Best known for his work on the atomic bomb, Leo Szilard made important contributions to twentieth-century physics, biology, and information theory. He is, however, an interesting figure apart from his scientific accomplishments. In brief, he did not merely do science, but lived it as well. He was a true believer in science and its potential to save the world. This intellectual biography of Szilard captures the visionary centerpoint of his passion for science and public activism. This work will be of interest to historians of science, physicists, and biologists. Contents: The Intellectual Landscape; The Thunderclap and Its Antecedents; Moving into Nuclear Physics; A Time of "Heartbreak and Frustration"; Down the Shaft; From Physics to Biology and Political Chivalry; Notes; Bibliography; Index.