This book provides a comprehensive study of when and how armed groups can be held accountable under international human rights law. Part I emphasises the added value of such a study for everyday life in the territory under control of an armed group, as opposed to an approach which focuses exclusively on international humanitarian law. In Part II this leads us to a more fundamental question: whether an armed group can be bound by international law at all. Fortin uses the concept of international legal personality, defined as ‘the capacity to be the bearer of rights and duties under international law’ (p. 71), to reach a positive answer: even without the status of belligerency, an armed group acquires legal personality under international law where it controls territory or people in default of its parent state. Part III shows that an armed group can be directly held accountable for international obligations accepted by the parent state. Thus, human rights obligations borne by armed groups stem from customary law, which can be found in the international human rights treaties and practices by treaty bodies, even though these treaties do not provide obligations of armed groups in their texts. In addition, the obligations can also be identified in treaties which explicitly mention obligations of armed groups. A few questions remain: How can the proposed understanding of legal status of armed groups as duty bearers in international law be reconciled with the last sentence of common article 3 of the Geneva Conventions? And which human rights obligations can and should be imposed on armed groups? Nevertheless, this book advances our understanding of difficult legal issues in internal armed conflict.