Tracing war as a legal concept from Roman times through to the twentieth century, Stephen Neff reveals its various roles as a law-enforcement operation, duel between states and a "crime against the peace." He also considers the post World War II definition of war as an international law-enforcement mechanism under U.N. auspices. Although unsuccessful, this attempt did help transform war into a humanitarian, rather than a policy problem. This book interests historians, students of international relations and international lawyers.