Diplomacy in pursuit of peace and security faces severe challenges not seen in decades. The reemergence of strong states, discord in the UN Security Council, destabilizing transnational nonstate actors, closing space for civil society within states, and the weakening of the international liberal order all present new obstacles to diplomacy. In Diplomacy and the Future of World Order, an international group of experts confronts these challenges to peace and conflict diplomacy—defined as the effort to manage others' conflicts, cope with great power competition, and deal with threats to the state system itself. In doing so, they consider three potential scenarios for world order where key states decide to go it alone, return to a liberal order, or collaborate on a case-by-case basis to address common threats and problems. These three scenarios are then evaluated through the prism of regional perspectives from around the world and for their potential ramifications for major security threats including peacekeeping, nuclear nonproliferation, cyber competition, and terrorism. Editors Chester A. Crocker, Fen Osler Hampson, and Pamela Aall conclude the volume by identifying emerging types of diplomacy that may form the foundation for global peacemaking and conflict management in an uncertain future.