Leo Szilard (1898-1964), a native of Budapest and naturalized US citizen elected to Academy
membership in 1961, was noted for his contributions to the fields of thermodynamics, biophysics, nuclear
physics, and the development of atomic energy. Szilard, experimenting in collaboration with Fermi, Zinn,
and Anderson, proved the possibility of a nuclear chain reaction, but he may be best known for his role
in the initiation of the Manhattan Project for developing an atomic bomb during World War II. Very early
after the discovery of uranium fission, Szilard, having moved to the US and realizing the military potential
of the discovery, attempted to get the US government interested in starting an atomic energy program.
With Einstein, Szilard in the summer of 1939 drafted a letter, signed by Einstein, to President Roosevelt
recommending such a program. The US atomic energy effort, which became known as the Manhattan Project in
1942, was finally begun at the end of 1941. In 1945, when the Manhattan Project had produced an atomic
bomb, Szilard circulated a petition, signed by a number of his fellow atomic scientists, asking that the
bomb not be used against Japan. After the war Szilard involved himself in efforts to control nuclear arms,
and abandoned nuclear physics for work in the field of biology. Some of his last work in this field was
published posthumously in the Proceedings of the NAS. He died in 1964, only three years after his election
to the Academy.
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