International history is the study of the interaction of historical forces across national boundaries. These interactions can be very broadly defined–to include demographic, cultural, and intellectual exchanges as well as military, political, and economic ones–while national identities themselves can be interrogated from an international or transnational perspective. Some University of Chicago historians are primarily concerned with international exchanges, and many others incorporate international or transnational themes into their scholarship or teaching, as do a wide variety of scholars in other departments and programs. Historians pursuing international or transnational topics can also draw on the resources of the Center for International Studies, with its affiliated area studies centers, and on a large number of international, transnational, or comparative workshops.