Scope and Content of Collection
Special Collections & Archives, UC San Diego
9500 Gilman Drive
La Jolla 92093-0175
Title: Leo Szilard Papers
Identifier/Call Number: MSS 0032
46.9 Linear feet
(111 archives boxes, 1 records carton, 2 card file boxes, 18 oversize folders)
Date (inclusive): 1898 - 1998
Abstract: Papers of Leo Szilard, nuclear physicist, biologist, and advocate of global arms control. Most of the material in the accession
processed in 1988 dates from the late 1930s to the early 1960s, the period following Szilard's move to the United States.
Materials from earlier years include patents, personal documents, and a number of letters. The collection documents Szilard's
work on the atomic bomb and his efforts on behalf of arms control and world cooperation. Prominent correspondents include
Enrico Fermi, J. William Fulbright, Otto Hahn, Hubert Humphrey, Frederic Joliot-Curie, Linus Pauling, Michael Polanyi, Jonas
Salk, Edward Teller, Harold C. Urey, and Eugene P. Wigner. Also included are copies of correspondence with Albert Einstein.
The accessions processed in 2000 contain further correspondence with prominent individuals, including Leslie Groves, John
F. Kennedy, Nikita Khrushchev, Max von Laue, and letters from Szilard to Gertrud Weiss Szilard, his wife (1936-1960, in German).
It also includes annotated drafts of the letter written with Albert Einstein to President Roosevelt disclosing developments
in nuclear fission. The papers include recent articles on Szilard, and documentation and memorabilia from programs and celebrations
of his life and work.
Box 116 removed, and Gertrud Weiss Szilard materials transferred to MSS 432 in 2014.
After digitization of the sound recordings and films in 2015, materials were consolidated and boxes 103 and 104 were removed
from the collection.
Leo Szilard and Aaron Novick Research Files. MSS 196. Special Collections & Archives, UC San Diego.
Gertrud Weiss Szilard Papers. MSS 432. Special Collections & Archives, UC San Diego.
Leo Szilard Letters to Gertrud Weiss. MSS 650. Special Collections & Archives, UC San Diego.
Lanouette/Szilard Papers. MSS 659. Special Collections & Archives, UC San Diego.
Scope and Content of Collection
Papers of Leo Szilard, nuclear physicist, biologist, and advocate of global arms control. The collection documents Szilard's
work on the atomic bomb and his efforts on behalf of arms control and world cooperation. The collection was processed in two
Accession Processed in 1988
The majority of the materials in the Szilard papers date from the late 1930s to the early 1960s, the period following Szilard's
move to the United States. Materials dating from earlier years include patents, personal documents, and a number of letters.
Prominent correspondents include Enrico Fermi, J. William Fulbright, Otto Hahn, Hubert Humphrey, Frederic Joliot-Curie, Linus
Pauling, Michael Polanyi, Jonas Salk, Edward Teller, Harold C. Urey, and Eugene P. Wigner. Also included are copies of correspondence
with Albert Einstein.
Arranged into twelve series: 1) BIOGRAPHICAL MATERIALS, 2) CORRESPONDENCE, 3) WRITINGS, 4) SUBJECTS AND ORGANIZATIONS, 5)
FINANCIAL RECORDS, 6) ADDRESSES, 7) GERTRUDE SZILARD MATERIALS, 8) PHOTOGRAPHS, 9) SOUND RECORDINGS, 10) FILM & VIDEO, 11)
ARTIFACTS, and 12) NEWSPAPER CLIPPINGS.
Accessions Processed in 2000
The accession processed in 2000 complements the first accession and contains correspondence with prominent individuals (including
Leslie Groves, John F. Kennedy, Nikita Khrushchev, Max von Laue, and letters in German from Szilard to Gertrud Weiss Szilard,
his wife), several writings by Szilard, recent articles about Szilard, and documentation of programs and projects celebrating
his life. Also included are letters written in 1939 between Szilard and international physicists related to attempts to keep
fission experiment results unpublished, and annotated drafts of the letter written with Albert Einstein to President Roosevelt
disclosing developments in nuclear fission. The papers date between 1921 and 1981.
Arranged into four series: 13) CORRESPONDENCE, 14) WRITINGS BY LEO SZILARD, 15) ARTICLES, PROJECTS AND PROGRAMS ON LEO SZILARD
and 16) MISCELLANEOUS MATERIAL.
Leo Szilard is best known for his pioneering work in nuclear physics, his participation in the Manhattan Project during World
War II, and his opposition to the nuclear arms race in the postwar era.
The son of an engineer and the scion of an affluent Jewish family, Szilard was born Leo Spitz on February 11, 1898 in Budapest,
Hungary. His family name was changed to Szilard in 1900. Szilard was a precocious child, and he took an interest in physics
at the age of thirteen. He attended public school in Budapest before being drafted into the Austro-Hungarian army in 1917.
In the army he was sent to officer's training school, but he was spared from active duty by a severe case of influenza. After
the war he remained in Budapest but, due to political unrest and a lack of suitable educational opportunities, he left for
Berlin in 1919.
In Berlin Szilard studied engineering at the Institute of Technology (Technische Hochschule), but his primary interest was
physics. He was attracted to the work of great physicists like Albert Einstein, Max Planck, Max Von Laue, Erwin Schroedinger,
Walter Nernst, and Fritz Haber -- most of whom were teaching in Berlin at that time.
In 1921 Szilard gave up his engineering studies and enrolled at the University of Berlin, where he studied physics under
Max von Laue, among others. He earned his doctorate -- cum laude -- in August 1922 after submitting his dissertation entitled
Uber die thermodynamischen Schwankungserscheinungen. In this work Szilard showed "that the Second Law of Thermodynamics covers
not only the mean values, as was up to then believed, but also determines the general form of the law that governs the fluctuating
values." The dissertation presented ideas relating to what would become the foundation of modern information theory.
Szilard began postdoctoral work at the Kaiser Wilhelm Institute in Berlin with Hermann Mark. Szilard's studies focused on
the anomalous scattering of X-rays in crystals and the polarization of X-rays by reflection on crystals. Between 1925 and
1933, he applied for numerous patents, often with Albert Einstein. One of the Szilard-Einstein patents covered the invention
of a new refrigeration system based on a method for pumping metals by a moving magnetic field. The two physicists hoped to
interest the company A.E.G. (the German General Electric company) in producing a practical refrigerator based on their patent.
Although this refrigerator was never produced, the refrigeration system was used effectively in the U.S in 1942 to develop
an atomic reactor.
In 1933, with Hitler's rise to power in Germany, Szilard moved to England. In London he collaborated with T.A. Chalmers at
St. Bartholomew's Hospital. There they developed the Szilard-Chalmers process, a technique to chemically separate radioactive
elements from their stable isotopes. Much of Szilard's activity during this period related to his efforts to register his
patents in England and to secure income with the help of the firm of Claremont, Haynes, and Company. Szilard's associates
in various ventures included Isbert Adams, Arno Brasch, T.M. Vogelstein, R. Kammitzer, and Benjamin Liebowitz. Szilard also
influenced Sir William Beveridge to found the Academic Assistance Council, an organization created to help persecuted scientists
leave Nazi Germany. Between 1935 and 1937 he worked as a research physicist at the Clarendon Laboratory, Oxford University.
It was on a street corner in London, in October 1933, that Szilard first conceived of the possibility of a nuclear chain
reaction. The possibility of such a chain-reaction -- the process essential for the releasing of atomic energy -- had been
dismissed by the eminent physicist Lord Ernest Rutherford. Szilard successfully proved Rutherford wrong.
Szilard visited the United States several times in the mid-1930s, and he began to consider a move to America as the prospects
for war in Europe increased. In 1938, at the time of the Munich pact, Szilard was a visiting lecturer in the United States.
He decided to shift his residence to New York in anticipation of England's weakening policy toward Germany and the impending
At the Pupin Laboratories at Columbia University, Szilard collaborated with Walter Zinn to research neutron emissions. They
discovered that two fast neutrons are probably emitted in the fission process, and that the element uranium might sustain
a chain reaction. Subsequent investigations with Enrico Fermi and Herbert Anderson, also at Columbia, demonstrated that a
system composed of water and uranium oxide approached the requirements for a self-sustaining chain reaction. Szilard elaborated
on a graphite uranium system in his manuscript entitled "Divergent Chain Reactions in a System Composed of Uranium and Carbon"
(later expanded into the "A-55 Report" for the Metallurgical Laboratory in Chicago) which was submitted and accepted (although
withheld) for publication in the
Physical Review on February 16, 1940.
With the start of World War II, Szilard became intensely concerned about the applications of the new atomic theories to the
development of weapons. Knowing that German nuclear research was at an advanced stage, he felt that the work being conducted
by him and his colleagues should be withheld from publication. Szilard and his colleagues Eugene Wigner and Edward Teller
hoped to gain the financial support of the United States Government in underwriting the cost of a definitive, large-scale
experiment to prove that a sustained nuclear chain reaction was possible. Together they enlisted the assistance and influence
of Albert Einstein. With Einstein's consent, Szilard drafted a letter, which was signed by Einstein and delivered to President
Roosevelt by Alexander Sachs in October 1939. This letter outlined the possibility of the chain reaction and its implications
for national defense.
Szilard's work on atomic energy intensified during World War II. With governmental support approved by President Roosevelt
and with the assistance of the National Bureau of Standards, Szilard began to procure graphite and uranium through negotiations
with suppliers like the National Carbon Company. These materials were necessary components for a large scale chain-reaction
experiment. From February 1942 to July 1946, Szilard worked as "Chief Physicist" for Arthur H. Compton at the Metallurgical
Laboratory of the University of Chicago. This Laboratory was one of the chief research centers for the development of the
atomic bomb, in what would come to be called the Manhattan Project.
On December 2, 1942, Szilard and his colleagues demonstrated the first nuclear chain reaction. This demonstration took place
in the graphite block reactor built under the grandstand at the University of Chicago's Stagg Field. This successful experiment
was in part the result of Szilard's atomic theories.
Throughout the Manhattan Project, Szilard was often frustrated by cumbersome government administration and security regulations.
Like other scientists involved in the project, he felt uneasy about the dominant role played by the military in the project.
Many of his memoranda from the period reflect these concerns.
Szilard viewed the production of the atomic bomb as a necessary counter-measure to the possibility of German nuclear development
and deployment, but he foresaw the global consequences of the proliferation of this weapon. After Germany surrendered, Szilard
organized his colleagues to press for limitations in the use of the atomic bomb. He drafted a letter to President Roosevelt
urging restraint in the use of the bomb, but the President died before the letter could be delivered. In the spring of 1945,
Szilard influenced a group of scientists to produce the Franck Report, which outlined the dangers of a nuclear arms race.
The report advised against the use of an atomic bomb against Japanese civilians, advocating instead a non-combat demonstration.
In July 1945 Szilard circulated a petition urging President Truman not to drop the atomic bomb on Hiroshima. A revised version
of this petition was eventually signed by 68 scientists at the Metallurgical Laboratory. It was strongly opposed by General
Groves, head of the Manhattan Project, on the grounds that such a petition would breach security and expose the existence
of the atomic bomb. The petition did not reach the president. After Japan's surrender Szilard worked to defeat the May-Johnson
bill, which sought to place atomic energy in the hands of the military.
After the war Szilard began to focus on biology, a field he had long been interested in. He resigned from the Metallurgical
Laboratory on June 1, 1946, and became a half-time professor of biophysics at the Institute of Radiobiology and Biophysics
at the University of Chicago. He also worked half-time for the University's Division of Social Sciences as Adviser to the
Office of Inquiry into the Social Aspects of Atomic Energy. For the academic year 1953-1954, Szilard served as a visiting
professor of biophysics at Brandeis University. In 1956, he became a professor of biophysics at the Enrico Fermi Institute
for Nuclear Studies at the University of Chicago. To broaden his knowledge of biology he often attended seminars and conferences,
such as the Cold Springs Harbor Symposium in New York.
Throughout the 1950s Szilard continued his biological research. In Chicago he collaborated with Aaron Novick to develop the
"chemostat," a device for "maintaining a multiplying population of bacteria under conditions not changing in time." Numerous
articles resulted from his research, including "Experiments with the chemostat on spontaneous mutation of bacteria," "Anti-mutagens,"
and "On the nature of the aging process." Szilard's theory of aging, a major outgrowth of his research, became a continuing
interest in his later life. Much of Szilard's research funding came from contracts and grants with organizations such as the
National Advisory Health Council and the Office of Naval Research. He also worked as a consultant to private industry, and
his patents for a "liquid-liquid extractor" were used by Podbielniak, Inc.
Szilard became increasingly active in public political activities during the Postwar period. In his lectures he advocated
nuclear arms control, world government, and an elite leadership role for the international scientific community. Many of his
ideas were inspired by the works of H.G. Wells, which he had read avidly as a young man. Wells's book
The World Set Free (London, 1914), which had predicted the development of atomic power, had made a great impression on Szilard when he read
it in 1932.
In 1947, Szilard published a "letter to Stalin" in the Bulletin of the Atomic Scientists. In the letter he urged world leaders
to openly exchange ideas in an effort to mitigate the growing Cold War. In his appeal he took a balanced view of the peace
process, blaming neither the U.S. or the Soviet Union for the situation. In the late 1950s Szilard's ideas inspired Albert
Einstein and Bertrand Russell to organize an international conferences of concerned scientists. The first conference took
place at Pugwash, Nova Scotia in 1957, and subsequent conferences, named after the location of the first meeting, have been
held throughout the world since then.
After 1958, with the increasing threat of nuclear war, Szilard's political activities intensified. Between October 1959 and
October 1960 he carried on a series of interactions with Soviet Premier Nikita Khruschev which culminated in a two hour interview
in New York. Szilard proposed the development of a Moscow-Washington "hot line," which could facilitate communications between
super-power leaders in the interest of global peace. With the election of President Kennedy, Szilard moved to Washington,
D.C., taking up residence at the DuPont Plaza Hotel. He criticized Kennedy's handling of the Bay of Pigs debacle and the President's
bomb shelter program. Szilard offered to personally intercede with Khruschev during the Berlin Crisis in 1961.
Throughout the early 1960s Szilard continued his advocacy of global cooperation. In 1961 he began a lecture tour which would
take him to eight college campuses. His first lecture, at the Harvard Law School Forum on November 17, 1961, was entitled
"Are We on the Road to War?" From these and other efforts came an organization known as the Council for a Livable World, a
political action committee which encouraged members to donate two percent of their income to designated political candidates.
In 1962, Szilard attempted unsuccessfully to organize informal meetings between lesser officials of both the United States
and the Soviet Union in what he termed the "Angels Project."
Szilard wrote extensively during this period. He suggested rules for nuclear age living in "How to Live with the Bomb and
Survive" (1960). He wrote a futuristic work of fiction entitled
The Voice of the Dolphins (1961). In this work Szilard had the dolphins describe the debacle of human society, out of which they have inherited the
earth. He carried on his writing during two courses of radiation treatments for bladder cancer in 1960 and 1962. While undergoing
these treatments in New York City's Memorial Hospital, Szilard also made an extensive series of tape recordings relating to
his life and his involvement in the Manhattan Project.
In July 1963, Szilard was appointed as a non-resident fellow at the Salk Institute for Biological Studies in La Jolla, California.
He had known Jonas Salk since the late 1950s, and many of Szilard's ideas had influenced Salk in the planning of the Institute.
Szilard moved to La Jolla in February 1964. There he intended to work in biophysics as a Resident Fellow of the Salk Institute.
But three months later, on May 30, 1964, he died of a heart attack.
Szilard lived a peripatetic life. After leaving Budapest in 1919 he had no true permanent residence. He stayed mostly in
hotels, and his associations with various universities were usually tenuous. Because he had no long-term institutional affiliations,
Szilard had difficulty in marshalling the material forces -- such as a clerical and laboratory staff -- needed to follow through
on many of his important ideas. Szilard was essentially a thinker, and he preferred to leave for others the tasks involved
in implementing his ideas.
Szilard's life gained some stability through his relationship with Dr. Gertrude Weiss. Weiss was a physician who had fled
Nazi Germany in 1930s. She met Szilard before the war, and the two were married in the United States in 1951. Still, the couple
often lived apart, and Szilard considered himself a "bachelor at heart."
For more detailed biographical information, see
Leo Szilard: His Version of the Facts, edited by Spencer Weart and Gertrude Weiss Szilard (Cambridge, Mass.: MIT Press, c1978) and the "Introduction" by Barton
Bernstein to Helen Hawkins, et al., eds.,
Toward a Livable World: Leo Szilard and the Crusade for Nuclear Arms Control (Cambridge, Mass.: MIT Press, c. 1987), p. xvii-lxxiv. Finally, a full-length biography of Szilard by William Lanouette has
been published entitled
Genius in the Shadows: A Biography of Leo Szilard, the Man Behind the Bomb.
Publication rights are held by the creator of the collection.
Leo Szilard Papers, MSS 32. Special Colllections & Archives, UC San Diego.
Selected materials from the collection have been digitized with grant funding from the National Historical Publication and
Records Commission (NHPRC).
Original audiovisual materials in the collection are restricted; digitized surrogates may be used. Fragile documents have
been restricted for preservation reasons, though photocopies and scans may be consulted.
Subjects and Indexing Terms
Atomic bomb -- United States
Nuclear arms control
Science -- Social aspects
Portrait photographs -- 1898-1977
Fermi, Enrico, 1901-1954 -- Correspondence
Szilard, Gertrud Weiss -- Correspondence
Fulbright, J. William (James William), 1905-1995 -- Correspondence
Hahn, Otto, 1879-1968 -- Correspondence
Humphrey, Hubert H. (Hubert Horatio), 1911-1978 -- Correspondence
Salk, Jonas, 1914-1995 -- Correspondence
Szilard, Leo -- Archives
Manhattan Project (U.S.)
Szilard, Gertrud Weiss -- Archives
Einstein, Albert, 1879-1955 -- Correspondence
Joliot-Curie, Frédéric -- Correspondence
Pauling, Linus, 1901-1994 -- Correspondence
Polanyi, Michael, 1891-1976 -- Correspondence
Wigner, Eugene Paul, 1902-1995 -- Correspondence
Weiss, Egon, 1919-2003
Teller, Edward, 1908-2003 -- Correspondence
Urey, Harold Clayton, 1893-1981 -- Correspondence