From two of the world’s leading intelligence and espionage historians comes the definitive—and most unsettling—account of the assassination of Leon Trotsky. Exiled from the Soviet Union and living under constant threat, Leon Trotsky believed that by 1937 he had found sanctuary in Mexico City. What he did not see was the vast clandestine machinery Stalin had already set in motion—one that beyond Europe and, crucially, into the United States itself. Drawing on newly uncovered evidence, this book reveals the previously untold role played by Stalin’s agents operating in America who helped make the assassination possible. At the center of the plot stood Ramón Mercader, a disciplined Soviet assassin using multiple false identities. Guided by his formidable mother, Caridad Mercader, he avoided overt violence in favor of patience, manipulation, and emotional infiltration. His most powerful weapon was not the ice axe he ultimately wielded, but trust—carefully cultivated through friendships, sympathies, and a romantic relationship with Sylvia Ageloff, a Brooklyn-born social worker whose true role in the assassination is reassessed here with startling clarity. Based on unprecedented access to classified documents in Mexico, the United States, and Russia, as well as unpublished correspondence from Trotsky’s personal guards, Nigel West and H. Keith Melton expose the fatal blind spots in Trotsky’s own security and thinking. His lifelong faith in personal loyalty, his dismissal of internal betrayal, and a measure of revolutionary hubris proved decisive in the final hours of his life. More than merely the story of how Leon Trotsky was murdered, this is a sweeping history of espionage, ideology, love, betrayal, and fatal miscalculation; it is the complete, never-before-told account of an assassination that changed the course of modern history. “This is the most compelling analysis of the new evidence!” –Oleg Kalugin, former KGB General and Chief of Counterintelligence “Experts in the art of espionage, West and Melton deliver a brilliant historical thriller on the most consequential and highest profile of Stalin's multitude of targeted political assassinations. Their newly uncovered archival research exquisitely lifts the veil on a sophisticated Soviet global spy operation with tentacles reaching into the U.S. A must-read for understanding how the Trotsky assassination spawned the Kremlin's playbook for creating a dictatorial regime full of fear and subjugation, which Putin follows to this day.” –Daniel O. Hoffman, retired CIA Senior Clandestine Services Officer H. Keith Melton has spent more than 35 years as a historical consultant to the U.S. and international intelligence community. A frequent lecturer at the CIA, FBI, and NSA, he also advises allied intelligence services worldwide. Melton has produced or appeared in over sixty documentaries on espionage and is the owner of the world’s largest private collection of intelligence artifacts―including the infamous ice axe that killed Leon Trotsky. He is a founding board member of the International Spy Museum in Washington, D.C., where he continues to serve as a permanent member of the Board of Directors. Nigel West is the author of some forty works of non-fiction on security and intelligence-related topics. He has also edited or contributed to a further thirty titles. He was voted "the experts'' expert" by a panel of spy writer assembled by the Observer. He is a specialist, a question-setter BBC TV''s Mastermind . and writes the Daily Telegraph obituaries for the intelligence community. He appears regularly as a commentator on security issues on Sky News, GBTV, CNN and other news outlets. He has also contributed to many podcasts and TV documentaries. He was chairman of the judges for the St Ermin''s Intelligence Book of the Year award and is on the editorial board of the International Journal of Intelligence and Counterintelligence.