In the winter of 1940, as Germany’s brutal bombing campaign against Britain dragged on, Joseph Goebbels poured out his frustrations in his diary. “When will that creature Churchill finally surrender?” he complained. “England cannot hold out forever!” What the Nazis’ minister of propaganda resented even more than the British prime minister’s stubbornness, however, were his powers of persuasion. Every time Churchill took to the airwaves it was as if he were injecting adrenaline-soaked courage directly into the British people. Still worse, Goebbels knew that growing numbers of Germans had begun listening, too. Convinced that tuning in to Churchill’s soaring speeches was not only a dangerous vice but also a traitorous act, he was determined to crush so-called “radio offenders” at any cost. “Every German,” Goebbels proclaimed, “must be clear in his mind that listening in to these broadcasts represents an act of serious sabotage.”