What is collective criminality in international crimes? Do individuals play different roles in pursuit of collective criminality? How do these international crimes vary from domestic ones, and to what purpose are the courts and tribunals which follow in their wake? This book presents an empirical examination of jurisprudence to answer these questions, and demonstrates that there are five categories of collective criminality. Considered through a lens of international criminology, these roles are shown to be necessary for the most serious of crimes to occur, creating social norms which produce conducive environments for the worst of human activity. This timely book demonstrates not only how atrocities occur, but also what steps are necessary to restore peace and normality in post-conflict societies.