This new handbook offers a combination of theoretical, thematic and empirical analyses of the international statebuilding regime, written by leading international scholars. Over the past decade, international statebuilding has become one of the most important and least understood areas of international policy-making. Today, there are around one billion people (or more than one-sixth of the world's population) living in some 50-60 conflict-affected, 'fragile' states, vulnerable to political violence and civil war. Some of these countries have recently seen war (and thus are in danger of relapse), while in others the dynamics of history, identity, economics, demography together with a weak state leave countries vulnerable to new escalations. The international community grapples with the core challenges and dilemmas of using outside force, aid, and persuasion to build states in the wake of conflict and to prevent vulnerable countries from lapsing into devastating violence. The emerging field of statebuilding is highly complex, and there continue to be deep challenges for global actors such as the United Nations in trying to build internal peace using external levers of power, money and, in some cases, military force. The goal of the handbook is to provide a comprehensive resource for this emerging area in International Relations. With nearly one-fifth of all countries globally chronically 'fragile', the need for international engagement to build states is just beginnign to emerge. Whether the measure is peacekeeping, or aid flows, there is still a basic appreciation that the approach and methods of international engagement are either woefully inadequate or downright harmful. Thus, a review of the statebuilding regime, which began in the wake of the Cold War era, will continue to be at the top of the international peace and security and development agendas for years to come. This handbook will be essential reading for students of statebuilding, humanitarian interevention, peacebuilding, development, war and conflict studies and IR/Security Studeis in general.