Half Life

The memo landed on Kim Philby's desk in Washington, DC, in July 1950. Three months later, Bruno Pontecorvo, a physicist at Harwell, Britain's atomic energy lab, disappeared without a trace. When he re-surfaced six years later, he was on the other side of the Iron Curtain.

One of the most brilliant scientists of his generation, Pontecorvo was privy to many secrets: he had worked on the Anglo-Canadi...