Kim Philby’s name is almost synonymous with Soviet espionage. But Philby was not alone: Along with Donald Maclean, Guy Burgess, Anthony Blunt, and John Cairncross, he was one of five "Cambridge spies" who penetrated the heart of British intelligence at the height of the Cold War.

Using recently declassified British, American, and Soviet intelligence records, Calder Walton, Ernest May Fellow in history and policy at Harvard’s Kennedy School of Government, explores the lives and treachery of these British elites from Cambridge University recruited into Soviet intelligence in the 1930s. He examines why they betrayed their homeland for Russia, how close British intelligence came to catching them, reveals another hitherto-undisclosed Soviet spy recruited from Cambridge, and evidence for a similar Soviet espionage ring at Oxford.

Walton assesses the damage the Cambridge spies did to the British secret state, and to Britain’s closest intelligence ally, the United States. He also sees the story as more than ancient history, and discusses how the legacy of the Cambridge spies is still reflected in contemporary Russian intelligence operations.

Walton is the author Empire of Secrets: British intelligence, the Cold War and the Twilight of Empire.

Listen to Calder Walton’s interview on the Not Old Better podcast with host Paul Vogelzang.