Humanitarian interventions have become a much more frequent form of assistance as a result of increases in violent conflicts within countries, a greater external willingness to intervene in such conflicts, and the increased incidence of natural disasters. The need to evaluate the effectiveness of such interventions has increased in consequence. In this volume, the Active Learning Network for Accountability and Performance in Humanitarian Action (ALNAP) has compiled for the first time an examination of the experiences of those practically engaged in humanitarian programme evaluation, and the lessons learned about the evaluation process. The case studies included in this volume are drawn from four continents, including Central Asia and the Balkans. They embrace the different kinds of humanitarian emergency that have afflicted so many people during the past decade. The volume addresses the context in which evaluations of humanitarian action take place; the actual process of doing evaluations; and the lessons for improving how such evaluations might be better undertaken in future. This pioneering volume is likely to be of great practical value to agencies and individuals engaged in both the delivery humanitarian assistance in complex emergencies and its evaluation.