What were the guiding themes of the discipline of International Relations before World War II? The traditional disciplinary history has long viewed this time period as one guided by idealism and then challenged by realism. This book reconstructs in detail some of the formative episodes of the field's early development and arrives at the conclusion that, in actuality, the early years of International Relations were preoccupied not with idealism and realism but with the dual themes of imperialism and internationalism. Thus, the beginnings of the discipline have resonance with the recently revived discourse of empire and the global status and policies of the United States as the world's sole superpower.