Since 2014, The Islamic State (henceforth IS, also referred to as ISIS), has invaded territories in Iraq and Syria and there is ample evidence that IS is committing international crimes such as genocide, crimes against humanity and war crimes. The Rome Statute covering the crimes states in its Preamble that the most serious crimes of concern to the international community as a whole must not go unpunished, and that their effective prosecution must be ensured by taking measures at the national level and by enhancing international cooperation. This book addresses the complexity of prosecuting these crimes and seeks to find the best venue to prosecute IS members. A special tribunal (also referred to as 'hybrid' court) combines international and domestic law in its statutes and rules. However, the establishment of one regional criminal tribunal, to be set in compliance with two different national legal orders, taking into account of two different ideologies (Western and Islamic), would be a significant legal challenge.