Neorealism or structural realism is a theory of international relations first outlined by Kenneth Waltz in his 1979 book Theory of International Politics. Alongside neoliberalism, neorealism is one of the most influential contemporary approaches to international relations; the two perspectives have dominated international relations theory for the last decade. Neorealism emerged from the North American discipline of political science, and reformulates the classical realist tradition of E.H. Carr, Hans Morgenthau, and Reinhold Niebuhr. Realists in general argue that power is the most important factor in international relations.