A special regime is a subpart of the international legal system. This is why, in international legal discourse, there are several different conceptions of a special regime. For the same reason as lawyers disagree about the proper definition of the concept of international law, not only do they have different conceptions of an international legal system but they also assume different definitions of the concept of a special regime. There are considerable differences among the different conceptions of a special regime. This observation raises questions about their relative utility. Chapter 1 suggests the adoption of the conception that characterizes special regimes as communities of practice – as it helps to manage and control the effect of legal fragmentation compared to other conceptions.