Today, the concept of culture is an inescapable part of international relations, from states’ use of “cultural diplomacy” to UNESCO statements on “cultural diversity.” Its significance is often unclear, however, in part because its history is poorly understood. What has been meant by this complex term, and how did it come to play such an important role in world politics? My book explores these questions through the systematic study of a key way that diplomats and political leaders have defined and applied the concept of culture: by drafting international agreements. Between the 1930s and the end of the Cold War, states across the world signed hundreds of agreements explicitly devoted to “culture,” including bilateral treaties, regional agreements, and open multilateral conventions. Using an innovative mixture of quantitative and qualitative methods drawn from conceptual history, the historical study of international relations and the digital humanities, my study charts the global history of these agreements, focusing on five cases in which powerful states used cultural agreements in ambitious and controversial efforts to reshape world order. Ultimately, the book asks how different ideas about human diversity shape the global organization of political authority. In this way, the book will make important contributions to the dynamic field of international intellectual history and, more broadly, to the growing interest in global studies in the humanities and social sciences.