Leffler is one of the most accomplished and distinguished historians of U.S. foreign policy, and this collection of his most influential and important essays over the last 50 years is a welcome addition to the literature in the field. Leffler adds to the value of the collection with an introduction and a running commentary that situates these essays in his own intellectual development. He began, like many of his peers, as an enthusiastic adherent of the historian William Appleman Williams, who saw economic imperialism as the main driver of U.S. foreign policy. But Leffler gradually came to believe that the complexity of the U.S. political system made it impossible for any single factor to play such a large role. Although he never lost sight of the vital role that economic considerations play in U.S. politics, Leffler saw other perspectives and other actors contesting and frequently overruling the recommendations and proposals of important pro-business lobbies and leaders. His skillful essays reveal him to be a scholar who was honest and courageous enough to let himself be instructed by the facts that he found.