Because of the activities of people like Klaus Fuchs, Harry Gold, and David Greenglass, the 1940s and 1950s can be called an age of

Klaus Fuchs, Harry Gold, and David Greenglass were involved in passing atomic secrets to the Soviet Union. Their activities were acts of spying, or espionage, during the early Cold War. Therefore, the period can be called an age of espionage.

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