Peace research is a component of the field of international relations (IR) that focuses on the causes of war and violence as well as the conditions of peace. The origins of peace research can be traced to the works of Plato, Thucydides, Hugo Grotius, Thomas Hobbes, and Immanuel Kant. The central debate in peace research revolved around the question of whether peace is to be defined simply as the absence of war and direct violence (“negative peace”) or the whether the concept encompasses both the absence of war and direct violence plus the presence of social justice (“positive peace”). Three primary waves of peace studies worldwide since its beginnings between the world wars can be identified: the first wave, roughly from the 1930s to 1960s, focused largely on the causes of war; the second wave was concerned with radicalization and democratization of peace studies; and the third wave saw the rise of two dominant fields—those of nuclear weapons, arms control and disarmament, and conflict resolution/management. During the 1990s, there was a renewed attention to research on topics such as sanctions, peacemaking, the concept of a culture of peace, environment, development, and conflict. Peace research and peace studies have in some ways brought about a transformation not only of dominant power structures, but also of the very concept of power itself. However, there are areas that need improvement, such as developing alternatives to armed conflict and injustice.