A Hungarian physicist, he was best known for encouraging Albert Einstein to warn President Roosevelt about the atomic bomb. He later worked with Enrico Fermi to construct the first nuclear reactor. He circulated petitions among the scientists demanding greater scientific input on the future use of atomic weapons. After the war, he continued to worked toward peaceful uses of atomic energy and international arms control.  

In 1937 he left England to take up a post at Columbia University in New York. During the 1930s, he advised scientists not to publish results of chain reaction research, fearing the misuse of its dangerous possibilities. But equally aware of the danger at that time of Nazi Germany developing an atomic bomb first, he pressed the US government to support nuclear research and in 1939 helped persuade Albert Einstein to write to President Roosevelt advocating the immediate development of the atomic bomb. Thus, Leo Szilárd became one of the key scientists involved in the Manhattan Project. Although Szilárd had suceeded in helping to create the nuclear bomb, he failed in his passionate attempts to restrain its use. After Hiroshima, he worked intensely to advocate the peaceful applications of atomic energy and the international control of nuclear weapons.

In 1946 Szilárd’s scientific priorities shifted from physics to biology. Jacques Monod explained the move in this way: “… because of its very complexity and uncertainties, biology needed ideas, many ideas to be discussed, tested, rejected or temporarily accepted, that is, precisely the kind of goods that he knew he could provide in abundance and enjoyed dealing with.” One of these abundant ideas was that a European laboratory for molecular biology should be established.  

In the autumn of 1962, Szilárd met with Victor Weisskopf and Italian physicist Gilberto Bernardini to discuss the laboratory. They then got in touch with a number of molecular biologists, including Sir John Kendrew, Francis Crick, Sydney Brenner and James Watson, all of whom showed interest. Slowly the idea began to take shape and in August of 1963, a meeting was held in Ravello, Italy, which resulted in three main proposals: 

• That the project should be European and not world-wide
• That in addition to a laboratory, fellowships and advanced teaching courses should be provided
• That a formal body known as the European Molecular Biology Organisation should be established 

Szilárd died in California in 1964. He was a scientist who was deeply concerned with world peace and with efforts to create what he called “a more livable world”.

In 1962, he founded the Council for a Livable World whose symbol is a dolphin; this same dolphin motif is incorporated in the library book-plates as a reminder of this aspect of his life’s work.

Further links about Leo Szilárd:

• Leo Szilárd – a Chronological Biography
• Leo Szilárd Online
• Interview with Leo Szilárd, “President Truman did not understand”
• The Register of Leo Szilárd papers at the Mandeville Special Collections Library, University of California, San Diego  

Books by or about Leo Szilárd held in the Library