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.”

What Goebbels rightly feared — with a prescience drawn from his own use of public opinion as a weapon — was the threat that a far greater master of words and ideas would unite the West in a resolute defense against Nazi domination. In “The Splendid and the Vile,” Erik Larson, the author of such earlier books as “In the Garden of Beasts” and “The Devil in the White City,” tells the story of how that feat was indeed accomplished during Churchill’s first year as prime minister, rescuing Western civilization from the edge of the abyss and leaving it free to continue to fight. Through the remarkably skillful use of intimate diaries as well as public documents, some newly released, Larson has transformed the well-known record of 12 turbulent months, stretching from May of 1940 through May of 1941, into a book that is fresh, fast and deeply moving.

As important as Churchill’s stirring and carefully calculated speeches was the audience that received them on both sides of the Atlantic. When we look back on history, the most dramatic events — Rudolf Hess’s desperate solo flight to Scotland, the attack on Pearl Harbor — often overshadow everything else. But Larson’s deft portraits show the essential connection that words created between the powerful and the powerless, capturing the moments that defined life for millions struggling to survive the decisions of a few. These small, forgotten stories, which Larson uses to such moving effect, make it possible for us to understand, even 80 years later, what made hearts race and break, and are best told by the people who experienced them, not only in a war room surrounded by military advisers but also in a London walk-up, alone. “My heart misses a beat whenever a car changes gear-up, or when someone runs, or walks very quickly, or suddenly stands still, or cocks their head on one side, or stares up at the sky, or says, ‘Sshh!’” a young Londoner wrote in her diary after enduring months of nerve-shattering bombings. “So taken all round my heart seems to miss more beats than it ticks!”