Drawing on numerous interviews and recently declassified documents, Hoffman’s latest book is a must-read for aficionados of Cold War spy thrillers. Few other works describe in such detail what it meant to run American agents in Cold War–era Moscow: elaborate ruses to fool the KGB, tests to determine whether a promising new agent was in fact a plant, and constant tension between demands for more information and the need to protect agents. At the center of Hoffman’s story stands the Soviet radar expert Adolf Tolkachev, who was deeply disillusioned with the Soviet system and determined to hand over whatever secrets he could to the United States. To a remarkable degree, he succeeded—until 1985, when he was betrayed by a disgruntled CIA employee. The picture of Tolkachev that emerges is complex. He sought large payments for his help, not to spend the money but simply to demonstrate his worth, while also gratefully receiving kitschy tokens of Americana for his son. Not only was his information about Soviet technology valuable, but so was his example: he demonstrated that good intelligence could be collected by old-fashioned espionage as well as advanced technology.