Peacekeeping operations have unintended consequences—a fact long ignored by both practitioners and researchers. The deployment of a large number of soldiers, police officers, and civilian personnel inevitably has various effects on the host society and economy. These consequences are especially serious when they cause harm to the local community, as in the case of sexual abuse and exploitation, corruption, or the creation of a false economy. Unintended side effects can also negatively affect the ability of a peacekeeping mission to achieve its mandate. Bringing together field experiences and academic analyses, this book investigates the unintended consequences of peacekeeping operations on individuals and groups, on the host society and economy, and on the troop-contributing countries. It also analyzes the degree to which the United Nations has tried to manage some of these side effects, as well as the UN’s accountability in the context of the international legal framework. The aim of the book is not to discredit peace operations but to improve the ways in which they are planned and managed. The contributors identify the need to develop a culture of accountability—one that includes procedures to anticipate unintended consequences and to monitor any side effects during the operation, so that steps can be taken to prevent and manage negative consequences as early as possible.