Adolf Hitler loved American movies. Every night at about 9:00, after the Führer had tired out his listeners with his hours-long monologues, he would lead his dinner guests to his private screening room. The lights would go down, and Hitler would fall silent, probably for the first time that day. He laughed heartily at his favorites Laurel and Hardy and Mickey Mouse, and he adored Greta Garbo: Camille brought tears to the Führer’s eyes. Tarzan, on the other hand, he thought was silly.

As it turns out, Hitler’s love for American movies was reciprocated by Hollywood. A forthcoming book by the young historian Ben Urwand, to be published by Harvard University Press in October, presents explosive new evidence about the shocking extent of the partnership between the Nazis and major Hollywood producers. Urwand, a former indie rock musician and currently a member of Harvard’s prestigious Society of Fellows, takes the subject personally: His parents were Jewish refugees from Egypt and Hungary. Digging through archives in Berlin and Washington, D.C., he has unearthed proof that Hollywood worked together with the Nazis much more closely than we ever imagined.

Urwand has titled his riveting book The Collaboration: Hollywood’s Pact With Hitler, and as you turn its pages you realize with dismay that collaboration is the only fitting word for the relationship between Hitler and Hollywood in the 1930s. Using new archival discoveries, Urwand alleges that some of the Hollywood studio heads, nearly all of whom were Jewish, cast their lot with Hitler almost from the moment he took power, and that they did so eagerly—not reluctantly. What they wanted was access to German audiences. What Hitler wanted was the ability to shape the content of Hollywood movies—and he got it. During the ’30s, Georg Gyssling, Hitler’s consul in Los Angeles, was invited to preview films before they were released. If Gyssling objected to any part of a movie—and he frequently did—the offending scenes were cut. As a result, the Nazis had total veto power over the content of Hollywood movies....