The role of the United Nations as the major international organization chartered to preserve peace and discourage aggression has broadened steadily since the Cold War ended. Regional security concerns are concomitantly replacing global ones as the superpower standoff fades from the world stage. The role of the military—particularly the United States military—is changing both to support UN efforts and to meet a spurt of regional instabilities that could affect U.S. national interests. The military may be called upon to support the United Nations in five mission areas: preventive diplomacy, peacemaking, peacekeeping, peace enforcing, and peace building. Two questions are paramount: How the military should carry out such missions, and, indeed, whether the military should be involved in some of them. To provide an appropriate forum for addressing the question of how and debating the matter of whether, the Institute for National Strategic Studies hosted the Symposium from which these Proceedings have emerged. After officials, authorities, and scholars had discussed the five missions, they analyzed UN operations in Bosnia, Somalia, Cambodia, and the Middle East. Using the lessons learned in those operations, they then projected two important considerations: (1) how existing international organizations and coalitions might support future UN missions, and (2) what the implications would be for the U.S. military. These Proceedings collect the very timely papers presented at the Symposium as well as summaries of the cogent analysis and lively debate that followed.