This book addresses the experience with international peace support operations in the 1990s and the lessons to be drawn. Renowned international experts analyze, from an academic or practitioner’s view, the key changes that occurred after the end of the Cold War. They discuss international cooperation in peace support operations including civilian and military aspects. In the post-Cold War era, peace support operations have become an essential instrument for the international community in reacting to crises and stabilizing conflict areas. At the same time, peacekeeping has undergone a fundamental transformation. This conceptual evolution is still under way. In order to improve the international response in future contingencies, it is important to debate the lessons learned. This book presents different points of view and focuses mainly on the following questions: How has the new conflict environment changed the character of peace support operations? What lessons can be drawn as far as international cooperation is concerned? And how should the various actors cooperate in order to meet these new requirements?