Fellow scientist Eugene Wigner sums up Szilard’s contribution to the creation of the atomic bomb: “While I [Wigner] could claim half authorship in these considerations, carried out by Szilard and myself, I wish to emphasize two points. First, that neither Szilard nor myself realized the fact that the slow neutron fission is due to the 235 isotope alone. This so extremely important realization is due to Bohr alone. Second, that the prediction that neutrons would be emitted during the fission process is entirely due to Szilard. I remember quite well when he mentioned it first.”

(MSS 659, Box 2, Folder 18)

Hans Bethe recalls Szilard’s role in the Manhattan Project and explains why the United States succeeded in building the atomic bomb before the Nazis.

(MSS 659, Box 2, Folder 25)

When Szilard learned about the completion of the atomic bomb, he immediately advocated against its use. While 155 scientists at the Metallurgical Laboratory in Chicago signed the petition, several others opposed it and even launched a counter-petition.

(MSS 32, Box 89, Folder 6)

Szilard's employment was terminated until patents being sorted out, August 4, 1943

(MSS 659, Box 2, folder 19)

Letter: Szilard to Captain Lavender regarding copies of his own patent agreements with the US, February 27, 1945

(MSS 659, Box 2, folder 18)

Szilard having been pressured to assign his invention of a nuclear chain reaction to the government. November 16, 1955

(MSS 659, Box 2, folder 18)