Early Years

Leo Spitz was born in Budapest Hungary on February 11, 1898 to middle-class Jewish parents, Louis Spitz, a civil engineer, and Thekla Vidor. He had two younger siblings, a brother, Béla, born in 1900, and a sister, Rózsi (Rose), born in 1901. On October 4, 1900, the family changed its surname from the German "Spitz" to the Hungarian "Szilard", a name that means "solid" in Magyar. Despite having a religious background, Szilard became an agnostic. Education

In 1916 Szilard enrolled as an engineering student at the Palatine Joseph Technical University in Budapest. He also briefly served in the army and was discharged honorably in November 1918. Convinced that there was no future for him in Hungary, Szilard left for Berlin on December 25, 1919, and enrolled at the Technische Hochschule (Institute of Technology) in Berlin-Charlottenburg. Becoming bored with engineering he switched to physics and transferred to Friedrich Wilhelm University (University of Berlin) where he attended lectures given by Albert Einstein, Max Planck, Walter Nernst, James Franck and Max von Laue. He also met fellow Hungarian students Eugene Wigner, John von Neumann and Dennis Gabor. His doctoral dissertation was "The Manifestation of Thermodynamic Fluctuations", praised by Einstein, and winning top honors in 1922. It involved a long-standing puzzle known as Maxwell's demon. The problem was thought to be insoluble, but in tackling it Szilard recognized the connection between thermodynamics and information theory. Career in Europe

Szilard was appointed as assistant to von Laue at the Institute for Theoretical Physics in 1924. In 1927 he finished his habilitation and became a Privatdozent (private lecturer) in physics. For his habilitation lecture, he produced a second paper on Maxwell's Demon, Über die Entropieverminderung in einem thermodynamischen System bei Eingriffen intelligenter Wesen (On the reduction of entropy in a thermodynamic system by the intervention of intelligent beings), that had actually been written soon after the first. This introduced the thought experiment now called the Szilard engine and became important in the history of attempts to understand Maxwell's demon. The paper is also the first equation of negative entropy and information. As such, it established Szilard as one of the founders of information theory, but he did not publish it until 1929, and did not pursue it further. Claude E. Shannon, who took it up in the 1950s, acknowledged Szilard's paper as his starting point. Throughout his time in Berlin, Szilard worked on numerous technical inventions. In 1928 he submitted a patent application for the linear accelerator, not knowing of Gustav Ising's prior 1924 journal article and Rolf Widerøe's operational device, and in 1929 applied for one for the cyclotron. He also conceived the electron microscope. Between 1926 and 1930, he worked with Einstein to develop the Einstein refrigerator, notable because it had no moving parts. In September, 1933, Szilard read an article in The Times summarizing a speech given by Lord Rutherford in which Rutherford rejected the feasibility of using atomic energy for practical purposes. Szilard was so annoyed at Rutherford's dismissal that he conceived the idea of the nuclear chain reaction using recently discovered neutrons. In early 1934, Szilard began working at St Bartholomew's Hospital in London studying radioactive isotopes developing the Szilard–Chalmers effect used in the preparation of medical isotopes. Move to New York City

In November, 1938 Szilard moved to New York City, taking a position at Columbia University. In January Niels Bohr brought news to New York of the discovery of nuclear fission in Germany by Otto Hahn and Fritz Strassmann, and its theoretical explanation by Lise Meitner, and Otto Frisch. When Szilard found out about it he immediately realized that uranium might be the element capable of sustaining a chain reaction. Szilard and Zinn conducted a simple experiment on the seventh floor of Pupin Hall at Columbia, using a radium-beryllium source to bombard uranium with neutrons. They discovered significant neutron multiplication in natural uranium, proving that a chain reaction might be possible. In collabaration with Enrico Fermi Szilard patented the nuclear reactor which was latter tested on 2 December 1942 under Stagg Field at the University of Cicago. Letter to President Roosevelt regarding the Atomic Bomb

Dated August 2, 1939 Szilard drafted a confidential letter to the President Franklin D. Roosevelt explaining the possibility of nuclear weapons, warning of German nuclear weapon project, and encouraging the development of a program that could result in their creation. With the help of fellow Hungarian friends Eugene Wigner and Edward Teller, he approached his old friend and collaborator Einstein and convinced him to sign the letter which resulted in the establishment of research into nuclear fission by the U.S. government, and ultimately he Manhattan Project and the atomic bomb. Roosevelt gave the letter to his aide, Brigadier General Edwin M. "Pa" Watson with the instruction: "Pa, this requires action!" Metallurgical Laboratory in Chicago

In January 1942, Szilard joined the Metallurgical Laboratory in Chicago and later became chief physicist. He also became a United States naturalized citizen a year later in March 1943. With a passion for the preservation of human life, Szilard hoped that the U.S. government would not use nuclear weapons and drafted the Szilard petition advocating demonstration of the atomic bomb. With the recommendation of J.R. Openheimer the Interim Committee instead chose to use atomic bombs against cities over Szilard and other scientists protests. Later, Szilard lobbied for amendments to the Atomic Energy Act of 1946 that placed nuclear energy under civilian control. After World War II

At the end of WWII Szilard in his late 40s ended his career in physics and became a microbiologist. In 1946 he secured a research professorship at the University of Chicago that allowed him to dabble in biology and the social sciences. He teamed up with Aaron Novick, a chemist who had worked at the Metallurgical Laboratory during the war. It was a field that Szilard had been working on in 1933 before he had the quest for a nuclear chain reaction. The duo invented the chemostat, a device for regulating the growth rate of the bacteria in a bioreactor. They also discovered feedback inhibition, an important factor in processes of growth and metabolism. Szilard gave essential advice to Theodore Puck and Philip I. Marcus for their first cloning of a human cell in 1955. Szilard married Gertrud (Trude) Weiss, M.D., in a civil ceremony in New York on October 13, 1951. Weiss took up a teaching position at the University of Colorado in April 1950, and Szilard began staying with her in Denver. His last years

In 1960, Szilard was diagnosed with bladder cancer. He underwent cobalt-60 radiation therapy at New York's Sloan-Kettering Memorial Hospital on a treatment regimen he designed himself. A second round of treatment with an increased dose followed in 1962. The doctors tried to tell him that the increased radiation dose would kill him, but he said it wouldn't, and that anyway he would die without it. The higher dose resulted in a cure and his cancer never returned. This treatment became standard for many cancers and is still used. Szilard helped create he Salk Institute for Biological Studies in La Jolla (San Diego), California, where he spent the last year of his life. He was appointed a non-resident fellow there in July 1963, and became a resident fellow in April 1, 1964, after moving to La Jolla in February. On May 30, 1964, he died in his sleep of a heart attack. His remains were cremated and his papers are in the library at the University of California in San Diego. In February 2014, the library announced funding from the National Historical Publications and Records Commission to digitize its collection of his papers, extending from 1938 to 1998.