This book critically examines the practice of international criminal justice based on the experience of war criminals who have been tried for their crimes. Presenting the perspectives of those commonly referred to as ‘genocidaires’, ‘war criminals’ or ‘criminals against humanity’, this book presents their experience of international criminal justice, and its impact on them. By presenting their points of view and their feelings about justice, it becomes possible to describe the way in which this branch of justice is apprehended by the perpetrators of mass crimes, to produce testimony about the lived penal experience, and to analyse the functioning of this institution through a new prism: that of the persons standing trial. From this perspective, a new analysis of international justice is produced: one that reveals its aporias, as it demonstrates the difficulties international criminal justice faces insofar as the justifications that support it are not all confirmed, and as some of the expectations placed on it are shown to be difficult to reach, if not clearly unattainable. Based on over 60 interviews carried out over a period of twelve years with persons tried by the International Criminal Tribunal for the former Yugoslavia and the International Criminal Tribunal for Rwanda, this book offers a unique analysis of the working of international criminal justice. This interdisciplinary book will appeal to those with relevant interests in law, criminology, sociology and criminology.