On August 20, 1940, Leon Trotsky invited a man he knew only as Jacques Mornard into his study. Mornard waited for Trotsky to sit, then smashed an ice pick he had hidden in his raincoat into Trotsky’s skull. For over a decade, Trotsky’s greatest enemy, Joseph Stalin, had been trying to arrange his murder. Stalin’s agents had hunted him across Europe and into a lonely, bitter exile in Mexico. He had liquidated Trotsky’s family and friends, and yet Trotsky had always escaped his clutches. The man who changed this all was Ramón Mercader, a minor Spanish aristocrat and Soviet agent who had posed as Mornard, a dissolute Belgian playboy, and infiltrated Trotsky’s inner circle.