Since the end of the Cold War, the UN has increasingly been called on to dispatch multinational forces to enforce the peace and rebuild political order. Building on an earlier Rand study of U.S.-led peacekeeping efforts, this book is one of the first to systematically examine these operations. The authors find that operations in Namibia, Cambodia, El Salvador, and Mozambique were successful thanks to great-power support, the cooperation of neighboring states, and the fact that the societies in question were exhausted by war; in Somalia and Bosnia, meanwhile, UN peacekeepers were overwhelmed and eventually replaced by larger U.S.-led forces. More recently, the Australian-led UN operation in East Timor managed to disarm combatants, establish new security forces, and sponsor elections. The authors show that UN forces are chronically undermanned and underfunded (U.S. nation-building missions, in contrast, tend to be launched with more ambitious mandates in more difficult circumstances) but encouragingly conclude that the UN's low-profile, small-footprint approach to nation building has succeeded more often than it has failed and is remarkably cost-effective -- offering a promising framework for peacekeeping in the future.