ABSTRACT
The period since the end of World War II has been marked by the proliferation of multilateral institutions, including international governmental organizations (IGOs) and international nongovernmental organizations (INGOs), to facilitate and promote international order and cooperation. Explanation of the bases and patterns of international interactions requires understanding both of why states find it in their interest to cooperate with one another and of the reasons they choose different means to achieve a measure of order and collaboration in an otherwise anarchic environment.
