Despite being an ally during World War II, the Soviet Union launched an all-out espionage effort to uncover the military and defense secrets of the United States and Britain in the 1940s. Within days of Britain's highly classified decision in 1941 to begin research on building an atomic bomb, an informant in the British civil service notified the Soviets. As the top-secret plan to build the bomb, called the Manhattan Project, took shape in the United States, the Soviet spy ring got wind of it before the FBI knew of the secret program's existence. Barely four years after the United States dropped two atomic bombs on Japan in August 1945, the Soviet Union detonated its own in August 1949, much sooner that expected.
The Soviets did not lack for available recruits for spying, says John Earl Haynes, espionage historian and author of Early Cold War Spies. What drove these college-educated Americans and Britons to sell their nations' atomic secrets? Some were ideologically motivated, enamored of communist beliefs, explains Haynes. Others were motivated by the notion of nuclear parity; one way to prevent a nuclear war, they reasoned, was to make sure that no nation had a monopoly on that awesome power.
