Crimes of atrocity have profound and long-lasting effects on any society. The difference between triggering and preventing these tragic crimes often amounts to the choice between national potential preserved or destroyed. It is also important to recognise that they are not inevitable: the commission of these crimes requires a collective effort, an organisational context, and long planning and preparation. Thus, the idea of strengthening preventative action has taken on greater relevance, and is now encompassed in the emerging notion of ''responsibility to prevent''. International courts and tribunals contribute to this effort by ending impunity for past crimes. Focusing investigations and prosecution on the highest leadership maximises the impact of this contribution. The ICC has an additional preventative mandate which is fulfilled by its timely intervention in the form of preliminary examinations. Moreover, when situations of atrocity crimes are triggered, its complementarity regime incentivises states to stop violence and comply with their duties to investigate and prosecute, thus strengthening the rule of law at the national level. The new role granted to victims by the Rome Statute is key to the ICC´s successful fulfilment of these functions. This new book of essays, which includes the author''s unpublished inaugural lecture at Utrecht University, examines these issues and places particular emphasis on the additional preventative mandate of the ICC, the ICC complementarity regime, the new role granted to victims, and the prosecution of the highest leadership through the notion of indirect perpetration. ''The work of Professor Olasolo breaks new ground in the academic field of international criminal law, as an analysis of the system as a whole. I therefore wish to express my congratulations for this work.''From the Foreword by Luis Moreno Ocampo Prosecutor, International Criminal Court, The Hague, 27 April 2011''[Professor Hector Olasolo''s] compilation provides an enormous source of easy reference to students, academia and legal actors in the field of international law. A look at the titles compiled in this volume demonstrates the present challenges to international criminal justice''.From the Preliminary Reflections by Elizabeth Odio Benito Judge and Former Vice-President, International Criminal Court, The Hague, May 2011''This collection, written by a brilliant and prolific scholar and practitioner of international criminal justice, is an insightful and important contribution to the existing literature…Each chapter in this collection is copiously footnoted and thoroughly researched, making it an important reference tool for scholars and practitioners in the field. Additionally and importantly, the chapters explore, without polemic, areas of controversy and dissent and thoughtfully and scrupulously set forth arguments for and against particular doctrinal choices.''From the Introduction by Leila Nadya SadatHenry H Oberschelp Professor of Law and Director, Whitney R Harris World Law Institute, Washington University School of Law; Alexis de Tocqueville Distinguished Fulbright Chair, Université de Cergy-Pontoise, Paris, Spring 2011