This book analyzes the provision of aid to countries that have undergone negotiated settlements to civil wars, drawing on recent experiences in Bosnia, Cambodia, El Salvador, and Guatemala. It focuses on the potential for peace conditionality, linking aid to steps to implement accords and consolidate the peace. The book explores how aid can encourage domestic investment in peace-related needs; the reconciliation of long-run peacebuilding objectives with short-run humanitarian imperatives; and the obstacles that donors' priorities and procedures pose to effective aid for peace. It concludes that investing in peace requires not only the reconstruction of war-torn societies but also the reconstruction of aid itself.