Who is accountable under international law for the acts committed by armed opposition groups? In today's world the majority of political conflicts involve non-state actors attempting to exert political influence (such as overthrowing a government or bringing about secession). Notwithstanding their impact on the course of events, however, we often know little about these groups, and even less about how to treat their actions legally. In this award-winning scholarship, Liesbeth Zegveld examines the need to legally identify the parties involved when internal conflicts arise, and the reality of their demands for rights. Her study draws upon international humanitarian law, human rights law and international criminal law to consider a fundamental question: who is accountable for the acts committed by non-state actors, or for the failure to prevent or repress these acts? This study will be of interest to academics, postgraduate students and professionals involved with armed conflict and international relations.