James Calder Walton is a British-American historian and barrister who is widely considered one of the world's leading experts on the history of espionage, intelligence, and national security. He is currently assistant director of the Intelligence Project at Harvard University's Belfer Center.^[2] He is general editor of the multi-volume Cambridge History of Espionage and Intelligence.^[3]

While on a junior research fellowship at Cambridge University, Walton was a lead researcher for Christopher Andrew's official history of the British Security Service (MI5), The Defence of the Realm (2009). The position gave Calder six years of privileged access to MI5 archives.^[4]

Empire of Secrets: British Intelligence, the Cold War and the Twilight of Empire (2013)

Walton's first book covered post-war British intelligence activities. It was reviewed favorably in The Journal of Imperial and Commonwealth History.^[5]

Spies: The Epic Intelligence War between East and West (2023)

An exposé of the history of Russian intelligence, it received favorable reviews from Graham Allison, Fiona Hill, Fredrik Logevall, Lawrence Freedman in Foreign Affairs, and Paul Kolbe, former CIA Chief of Central Eurasian Division, who called it "the definitive compendium of intelligence operations in the Cold War".^[4][6]

Walton's work has been published widely including in Foreign Affairs, Foreign Policy, CNN, Time Magazine, The New York Times, The Washington Post, The Sunday Times, POLITICO, Newsweek, Prospect Magazine, the BBC, NPR, PBS, C-SPAN, Fox News, NewsNation, and academic peer reviewed journals such as Intelligence & National Security and the Texas National Security Review.^[2]