The debates surrounding humanitarian intervention and the responsibility to protect concern a series of central and interrelated issues in International Relations, international law, and political philosophy. These include the relationship between state sovereignty and human rights, the reasons for state behaviour, the role and adequacy of the United Nations, and whether states have a moral and legal obligation to protect those beyond their borders. This major work provides a detailed and systematic understanding of these political, legal, and ethical debates surrounding humanitarian intervention and responsibility to protect as they have evolved since the 1990s. Divided thematically, Volume I considers more closely the politics of humanitarian intervention, Volume II focuses on the international law on humanitarian intervention, Volume III considers the ethical issues, and Volume IV focuses explicitly on the responsibility to protect doctrine. This Major Work is designed to be a key reference for those interested in humanitarian intervention and the responsibility to protect from a wide range of fields, including International Relations, political science, international law, and political philosophy. Volume One: The Politics of Humanitarian Intervention Volume Two: The International law on Humanitarian Intervention Volume Three: The Ethical Issues Surrounding Humanitarian Intervention Volume Four: The Responsibility to Protect and Humanitarian Intervention