Frisch playing the piano at the British Mission Party, September 22nd, 1945. Otto Robert Frisch (October 1, 1904 - September 22, 1979) was a Jewish Austrian-British physicist. The rise of Hitler in 1933 made Frisch make the decision to move to London where he worked on cloud chamber technology and artificial radioactivity. He followed this with a five year stint in Copenhagen with Niels Bohr where he specialized in nuclear physics. With the outbreak of WWII he and Rudolf Peierls produced the Frisch-Peierls memorandum, which was the first document to set out a process by which an atomic explosion could be generated. This memorandum was the basis of British work on building an atomic device and also that of the Manhattan Project on which Frisch worked as part of the British delegation. At Los Alamos, one of his tasks was to accurately determine the exact amount of enriched uranium which would be required to create the critical mass. In 1946 he returned to England to take up the post of head of the nuclear physics division of the Atomic Energy Research Establishment and spent much of the next thirty years teaching at Cambridge. He died in 1979 at the age of 74.