Klaus Fuchs (born 29.12.1911) is a German theoretical physicist and a member of the Academy of Sciences of the GDR (1972). He was born in Rüsselsheim (now in the FRG). He studied at the universities of Leipzig and Kiel. In 1933 he emigrated, first to Paris, then to England. In 1937 he received the degree of Doctor of Philosophy at the University of Bristol, and in 1939 the degree of Doctor of Science at the University of Edinburgh. In 1941—46 he worked at the universities of Birmingham and Columbia and at the Los Alamos laboratory, and in 1946 —50 at the Atomic Centre at Harwell.
In 1959 —78 he was deputy director of the Central Institute for Nuclear Research in Rossendorf (GDR).
His work was in the field of the quantum theory of the solid state, statistical mechanics, field theory, nuclear physics, the physics of nuclear reactors, nuclear power, and philosophical problems of physics. In particular, he developed methods of solving the transport equation in reactor theory, substantiated the importance of breeder reactors for the development of nuclear power, and studied the burn-up cycle of nuclear fuel in a reactor and questions of diagnostics at nuclear power stations.