Building peaceful nation-states which respond to the aspirations of their citizens takes strong leadership, both international and domestic. The international community has an important role to play in assisting countries to avoid, contain, and recover from conflict, and the recent past demonstrates how much can be achieved when global and national incentives align, and program implementation is appropriately designed and well-managed. Too often, though, efforts have failed to decisively address the motives and opportunities which help to mobilize violent conflict; to integrate political, security, and development approaches; or to align local, national, regional, and global actions. As a result, some areas have seen new waves of conflict and violence in recent years and some “post-conflict countries” have not yet managed to make a decisive shift to successful and stable development. The goal of the World Development Report 2011 is to contribute concrete, practical suggestions to the debate on how to address conflict and fragility. It will discuss trends, causes, consequences, reviewing key thinking on the evolution of violent conflict and fragility and on its causes and assess the human and economic devastation caused by various types of conflict. It will also analyze the evolution of policies designed to address conflict and fragility, and will assess the extent to which they have been effective in helping prevent or resolve conflict.