A new account of the Cambridge Five that reveals, from Russian sources, how their spying changed the world 
From the 1930s until at least the early 1950s, five British insiders—diplomats, intelligence officers, a civil servant—handed the Soviet Union its most closely guarded secrets, from Foreign Office traffic to intelligence on Britain's atomic programme. Recruited at Cambridge in the slump of the 1930s, they went on spying long after any anti-fascist cause could explain it. But what did the Cambridge Five actually contribute to the system that recruited them?
Drawing on Russian archives never previously used, Jonathan Haslam reconstructs their relationship with Stalin's Russia. He finds Moscow persistently wary of them, suspicious that spies so productive had to be feeding disinformation. But Stalin himself had no such doubts: their reports reached his desk unfiltered, and he acted on them. The Five went on to shape Soviet policy for years.
Haslam follows the Five from recruitment to their lives after exposure, and shows how the intelligence they supplied helped bring the Cold War into being.