William Dodd was an unlikely ambassador. At age 64, the brainy historian craved nothing more than a quiet berth to complete his life's work, a four-part volume entitled The Rise and Fall of the Old South. But in 1933, when Dodd accepted President Franklin D. Roosevelt's offer of an ambassadorship to Germany, it soon became clear that Berlin wasn't going to provide Dodd the peace and quiet he was hoping for.

Erik Larson (The Devil in the White City) finds in William Dodd and his family a story of complexity, depth, sympathy, and all-too-human error in his newest, In the Garden of Beasts. In 1933, Hitler had yet to consolidate power, and it was possible for an American and his family to settle comfortably into Berlin society, socializing with members of the Nazi Party and even, in the case of Dodd's daughter Martha, pursuing an affair with the head of the Gestapo, Rudolf Diels.

If the idea of an American girl cheerfully canoodling with a Gestapo chief seems grotesque now, Larson offers the valuable reminder that early American policy in regard to Nazi Germany wasn't exactly proactive. Roosevelt was slow to speak out against the Nazi regime, despite the "brutal spasm of state-condoned violence" that swept Germany upon Hitler's ascent to power. In the 1930s, it was widely held that "any campaign that explicitly and publicly sought to boost Jewish immigration to America could only lead to [political] disaster"; even America's foreign consulates were discouraged from meeting their quota of political refugees. Larson also provides compelling anecdotal evidence of the anti-Semitism pervasive among the state department's senior officials, and, to a lesser extent, among the Dodds themselves.

For these reasons, along with a sheer unwillingness to believe the worst, Dodd and other observers for too long counted on moderate elements within the German government to pull Hitler's excesses into line. (It didn't help that Dodd was distracted by the internal politics of diplomacy: He drew resentment both within his embassy and in the state department for his perceived stinginess.) It took first-hand experiences of Nazi violence—as when Martha and her brother witnessed an Aryan girl, head shaved, paraded through the street for having married a Jew—for Dodd to fully acknowledge what some of his friends in Germany had been insisting all along: That Hitler was bent on war; that America's increasingly isolationist tendencies must be reversed. Even then, Dodd was still years ahead of American foreign policy, and his warnings fell on largely deaf ears, garnering him the designation "the Cassandra of American diplomats."

The Dodds' story is an inherently interesting one—but then, historians have long proven adept at sucking the life out of inherently fascinating stuff. Not so Larson—skillful storytelling and elegant integration of his considerable research keep this historical account moving at a novel's pace. (It doesn't hurt that he's got Martha Dodd around to spice things up. In addition to the Gestapo chief, her active sex life featured a Russian spy, a German prince, and writer Thomas Wolfe. In one of many such observations, Larson dryly explains that the leather sofa in her parents' library was "an asset in her romantic life.")