This big book has no longueurs, and even gains momentum as it turns to the present day. Mr. Putin’s invasion of Ukraine serves as a capstone to Mr. Walton’s century long story, though he knows that the Cold War between Russia and America will not be the story of the 21st century. Accordingly, he looks to shed light on America’s rivalry with China.

—Jeremy Black, The Wall Street Journal

“a pioneering study of espionage from 1917 to the present day.”

—Robert Service, professor of Russian History at Oxford University

“a riveting history of espionage”—The Economist

“Calder Walton’s deeply researched and artfully crafted book offers a masterclass in 20th century and contemporary history. It is rich with trenchant analysis, surprising details, cautionary tales, and unique insight into the ‘hundred years war’ between American and Russian intelligence agencies. Spanning the Bolshevik Revolution to the war in Ukraine, it is essential reading for anyone trying to understanding the complicated trajectory of current events.”

—Fiona Hill, deputy assistant to the U.S. president and senior director for European and Russia on the U.S. National Security Council from 2017 to 2019

“A masterpiece! The intelligence report on Russia and Ukraine in February 1922 with which Spies begins could have been written on the eve of Putin’s invasion a hundred years later. A major obstacle to understanding the current crisis, triumphantly overcome by Calder Walton, is Historical Attention-Span Deficit Disorder. 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 of modern and contemporary history at the University of Cambridge and author of The Defence of the Realm: The Authorized History of MI5

“Walton lifts the veil on the multifarious clandestine operations Russia and the West conducted against one another for over a century. The book makes major contributions to the study of espionage, most especially by highlighting the importance of leadership. . . . Walton’s coverage of Soviet and, later, Russian propaganda holds great value for understanding Russia’s efforts under current Russian President Vladimir Putin to use asymmetric espionage as a comparative advantage.”

—Daniel Hoffman, a former senior executive in the CIA’s Clandestine Services.

“Calder Walton’s Spies takes the reader behind the veil of classification to the world of spying and spies’ impact on history.”

—Graham Allison, Douglas Dillon Professor of Government at Harvard University and author of the bestselling Destined For War: Can America and China Escape Thucydides’s Trap?

“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. This volume will engross the general reader and policy maker alike, not least because it provides an unsettling window into the behavior of the second challenger, the People’s Republic of China.”

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

Spies grabs you from the opening page and never lets go. One of our foremost historians of the East-West intelligence war takes us deep inside this grand and often spine-chilling struggle, which predated the Cold War and still rages today. Authoritative, sweeping, chock full of fresh and riveting details, this is a gem of a book.

—Fredrik Logevall, Pulitzer Prize-winning author of Embers of War

“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 chief of CIA’s Central Eurasian Division