When University of Chicago professor William Dodd assumed the post of U.S. ambassador to Germany in 1933, he hoped for an undemanding position that would allow him spare time to write a book. At the time, few in the United States or Europe considered then-Chancellor Adolf Hitler a serious threat, and few expected him to remain in power long. Dodd was no exception, says Erik Larson, author of In the Garden of Beasts: Love, Terror, and an American Family in Hitler's Berlin. Having studied in Germany as a college student in the 1890s, Dodd began his term as ambassador with...