As an historian of intelligence and global security at Harvard University’s Kennedy School of Government, I study the hidden histories of great power conflicts—espionage, subversion, sabotage, past and present. Read More >

I write about public policy.

Helping to run the Applied History Project at Harvard’s Kennedy School, I engage widely with the public and policy-makers. Through commentary, and by contributing to broadcast programs, my work brings historical perspectives to present-day intelligence and national security affairs. Read More >

I’ve written
two books.

My first book, EMPIRE OF SECRETS (Harper-Press 2013) is a gripping account of British intelligence during the last days of the empire. My new book, to be published in 2023, is SPIES: The Epic Intelligence War Between East & West (Simon & Schuster/Little Brown) and will take readers inside the shadow conflict that has raged between Russia and the West for over a century. Read More >

I Comment on Current Events.

“A masterpiece!...” —Christopher Andrew “A gripping, authoritative work.” —Kirkus Reviews


Published in 2023, SPIES takes readers inside the intelligence war that has raged between Russia and West for over a century.

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“The book we have all been waiting for.” —Brendan Simms

Praise for the Book

“A masterpiece!...As Spies vividly demonstrates, we are living through the latest stage of an Epic Intelligence War Between East and West which began a century ago and shows no sign of ending.”

—Christopher Andrew, emeritus professor at Cambridge and author of Defend the Realm: The Authorized History of MI5

“Calder Walton has written the definitive compendium of intelligence operations in the Cold War, and their critical, if hidden, influence in shaping events and outcomes.”

—Paul Kolbe, former head of CIA’s Central Eurasian Division

“A thorough history of a century of conflict between Britain and America and the East...A gripping, authoritative work.”

—Kirkus Reviews

“Spies is the book we have all been waiting for. Calder Walton is one of the leading intelligence historians of his generation, and his epic account—replete with human drama and tragedy—shows that Russia’s struggle against the West neither began with the Cold War nor ended with the disintegration of the Soviet Union.”

—Brendan Simms, professor in the History of International Relations at Cambridge and author of Europe: The Struggle for Supremacy