Szilard was born in Budapest on February 11, 1898. He had studied only a year at the Technical Academy in Budapest before he was drafted into the army. His military experience was so unpleasant that he became a life-long pacifist.

After returning to civilian life, Szilard left Hungary to enroll first at the Technical Academy at Charlottenburg and then at the University of Berlin, where he received a Ph.D. in nuclear physics in 1922. The rise of Hitler convinced Szilard, as it did so many other Jewish scientists at the time, to flee Germany. He traveled first to London in 1934 and then, four years later, to the United States. He became an American citizen in 1943.

While in London, Szilard conceived of the notion of a nuclear chain reaction. "It occurred to me," he wrote, "that a chain reaction might be set up if an element could be found that would...