From the mid-1930s through the early 1960s, the Soviet Union benefited from the services of five British traitors. Reams of classified documents transferred from British files and offices to those of the Soviet’s. During the height of World War II and the Cold War which followed, classified information shared between the United States and Great Britain received an eager welcome from the Soviets. The traitors sent so much information to their Soviet handlers that some in the NKVD/KGB questioned its value. Others were simply overwhelmed by the amount of data received, and had insufficient time to properly analyze it all. Much of the damage done by the group originally labeled the Cambridge 4, later expanded to 5 when another traitor’s activities came to light, remains unknown.