Abraham Pais is the acclaimed author of the definitive biographies of Albert Einstein and Niels Bohr, two of the twentieth century's greatest scientists. In this new book, he turns his attention to 14 other scientists, all distinguished in their own right, but who had appeared as the supporting cast to his previous biographies: scientists such as Paul Dirac, Wolfgang Pauli, Mitchell Feigenbaum, and John von Neumann. In each case, Pais presents a blend of the personality and achievements of the scientist, assisted by his deep knowledge of physics and his personal acquaintance with the subject.