As the secrets of atomic energy were being revealed in Europe in 1938 and 1939, Hitler was invading Czechoslovakia and Poland, sparking off the Second World War. The Nazis stepped up their persecution of the Jews. Jewish scientists were condemned for their race and for their "Jewish physics," which the Nazis claimed were diseased and corrupt. The Nazis’ anti-Semitism caused many leading scientists, including Max Born, James Franck, Edward Teller, Leo Szilard, and Eugene Wigner, to flee to America where they all would play an instrumental role in the development of the atomic bomb. One top physicist who did not flee from the Nazis was Werner Heisenberg. In deciding to stay in Germany, Heisenberg became a tool of the Nazis and eventually headed the German effort to build atomic weapons.

Enrico Fermi was another European scientist who was affected by Hitler...