This volume is the second part of an English School project focusing on the position and role of the United States in international society. With a shift in focus to the twentieth century and a specific interest in how US practice has influenced and, in turn, how it has been influenced by developments in world politics, the expert contributors consider the derivative primary institutions of international society, and the historically specific shape of the practices of the foundational institutions. This volume will appeal to students in international relations, diplomacy, and international history, as well as established researchers and academics. The book should also be of interest to a general audience versed in diplomacy, foreign policy, international history, and historical sociology.