Ten years aft er its formal embracement at the 2005 World Summit, the concept of responsibility to protect (R2P) has become a very popular subject of academic inquiry. The Peace Palace Library catalogue lists well over 550 entries on the topic in this period. These contributions address a large variety of different topics relating to the contents, (legal) nature and application of the concept. In the face of factual scenarios that potentially lend themselves to an invocation of the R2P (Syria is an obvious example), such inquiries remain critical.

Yet, as the discussion on nature and contents of the concept continue, larger questions emerge. Concepts such as the responsibility to protect do not stand on their own. They are connected to, and interact with, a dense fabric of other concepts, principles and processes. In a way, it is a sign of maturation of a concept that attention shift s from the contents and nature of a concept as such, to such wider ramifications. Just as the debates on human rights law and international environmental law at one point shift ed to the impacts of the relevant rights and obligations on other fields of international law, so too questions are being asked about what the concept of R2P does and can mean for the wider system of international law.

The present volume is a very welcome addition to these broader inquiries. The main thesis of its editors, Richard Barnes and Vassilis Tzevelekos, is that that the concept of R2P has transformative effects or at least a transformative potential. At one level, that potential relates to broader shift s in international law, notably the shift from bilateralism to multilateralism or community interests. At another, and more specific level, such transformative effects may relate to such themes as protection of human rights, international criminal law, and the practice of the Security Council.

Of course, such transformation is unlikely to be caused by the concept of R2P alone. The point that emerges throughout the volume is that the concept of R2P is, at the same time, a consequence of more fundamental developments and, in an iterative process, a contribution to such developments.