With the end of the Cold War, the subject of weapons proliferation has acquired new interest and prominence. So too have questions about the nature of the world order that will succeed the structure of the last fifty years. This study explores the connections among these topics. It describes the prevailing conceptual model of nuclear proliferation, evaluates proliferation's changing technical features, considers economic and political factors bearing on its future rate and character, and speculates about proliferation's implications on the post-cold-war world order. It also considers the role of international public policy in meeting proliferation's challenges. Arguing that updated approaches are needed, the analysis emphasizes cooperative over coercive approaches to order. It concludes with an assessment of progress to date in meeting these new challenges, arguing that the new agenda is only slowly coming into focus.