This comparative study is concerned with the causes - and consequences - of failures to fulfill pledges to aid postconflict and transitional societies. In each of the six case studies, the coauthors first establish the sources, composition, and objectives of pledged aid and examine aid conditionality, delivery, and coordination. They then trace aid absorption, benefits, and impact on peace building and recovery. Finally, they assess the causes, consequences, and lessons of pledge gaps: What explains shortfalls in aid delivery? What social, economic, and political difficulties have ensued? And what does the experience suggest for future multilateral efforts at transition assistance? Good intentions notwithstanding, it is clear that recurrent delays and failures in aid follow-through can threaten vulnerable polities whose collapse would endanger regional peace and security.