Peacebuilding involves a range of measures targeted to reduce the risk of lapsing or relapsing into conflict by strengthening national capacities at all levels for conflict management, and laying the foundations for sustainable peace and development. Many cease-fires and peace agreements in civil wars are primarily unsuccessful and give way to renewed, and often escalated, violence. Progress is often incremental, in some cases spanning decades. Many peace processes become interminably protracted, lengthy and circular negotiations in which concessions are rare, and even if fragile agreements are reached they stumble at the implementation phase. Given the huge material and human costs of a failed peace process, the consolidation of peace processes and dealing with threats to implementation are crucial areas of scholarship and policy analysis. States are increasingly turning to it for solutions to burgeoning peace and security problems. But are the United Nations and its agencies equipped to tackle the new security challenges in addition to such global issues as drugs, the environment, the oceans, or mass migration. This Book, Obstacles to Peacebuilding, explores the factors that obstruct conflict settlement by focusing on the phenomena of spoilers and spoiling groups and tactics that actively seek to hinder, delay, or undermine conflict settlement through a variety of means and for a variety of motives. The countries that were better off to begin with, institutionally and economically, were better off at the end of nation-building interventions than were those that had greater limitations at the start. Nevertheless, almost all countries were meaningfully better off than when the operations began. Most post-Cold War interventions have been followed by improved security, some democratization, significant economic growth, and modest improvements in human development and government effectiveness. These outcomes have been achieved, in most cases, with only a modest commitment of international military and civilian manpower and economic assistance. The studies in this compilation by the contributors shed light on the process of peacebuilding and its obstacles.