This book provides an in-depth introduction to, and analysis of, the issues relating to the implementation of the Responsibility to Protect principle in international relations.The Responsibility to Protect (R2P) has come a long way in a relatively short space of time. It was endorsed by the General Assembly of the UN in 2005, and unanimously reaffirmed by the Security Council in 2006 (Resolution 1674). UN Secretary-General Ban Ki-moon has identified the challenge of implementing R2P as one of the cornerstones of his Secretary-Generalship. The principle has also become part of the working language of international engagement with grave humanitarian crises and has been debated in relation to almost every recent major international humanitarian crisis ' including Sudan, Sri Lanka, Myanmar, Georgia, the Democratic Republic of Congo, Chad, Darfur and Somalia.Yet evidence abounds of international disquiet: the original report was denounced by Arab and Asian members of the Human Rights Council, for example..The principal themes of this book are:The nature of the R2P principleImplementation challenges (especially the UN Secretary-General's implementation agenda, the politics of implementation, and the relationship between R2P and international law);Key themes in implementation (focusing on the prevention of genocide and mass atrocities, strengthening the UN's capacity to respond, the role of regional organizations and the place of women in the R2P agenda).By focusing mainly on the question of implementation, this book makes a unique contribution, building on the first generation of books on R2P that focused on the principle's origins and scope, and thereby introducing readers to contemporary debates about the issue and providing the first book-length analysis of the implementation agenda.The book will be of great interest to students of IR, foreign policy, security studies and politics.