The scientist who came in from the cold: Heinz Barwich's flight from the GDR

The arms race between the superpowers made spying on science and technology very important during the Cold War. However, whether Western secret services managed to recruit valuable sources in the research laboratories of the Soviet Union is a subject about which very little is known. This article shows that in the early 1960s the distinguished East German physicist Heinz Barwich did indeed spy for the Central Intelligence Agency (CIA) within the Joint Institute of Nuclear Research, near Moscow. It also demonstrates that the Berlin Wall, built in 1961, had a considerable impact on Western espionage in East Germany.