By nature, core international crimes have indistinct factual parameters. War crimes, crimes against humanity, and genocide generally occur on a massive scale, spread out over a large geographical area and a long time span, involving many perpetrators at various distances from the crime scene(s). These characteristics make international crimes difficult to demarcate from start to finish. This book addresses such delineation difficulties by exploring the jurisdictional and factual boundaries of international criminal prosecutions. This entails researching those legal aspects that influence demarcation: jurisdiction (in terms of scope as well as institutional influence), charges, and identifying material facts by adequately distinguishing them from background information and evidence for the purpose of the indictment.