Hans Albrecht Bethe (1906-2005) being interviewed by journalists. Bethe, German-American nuclear physicist, won the Nobel Prize in Physics for his work on the theory of stellar nucleosynthesis. He also made important contributions to quantum electrodynamics, nuclear physics, solid-state physics and astrophysics. During World War II, he was head of the Theoretical Division at the Los Alamos laboratory, where he played a key role in calculating the critical mass of atomic bombs, and did theoretical work on the implosion method used in both the Trinity test and the "Fat Man" weapon dropped on Nagasaki, Japan. Bethe also played an important role in the development of the larger hydrogen bomb. He later campaigned with Albert Einstein in the Emergency Committee of Atomic Scientists against nuclear testing and the nuclear arms race. He influenced the White House to sign the ban of atmospheric nuclear tests in 1963 and the 1972 Anti-Ballistic Missile Treaty, SALT I.