This volume continues the work of the Preparatory Commission of the International Criminal Court by developing ‘elements’ for ordering, instigating and aiding and abetting the commission of international crimes under Article 25(3)(b) and (c) of the Rome Statute. The development of proposed elements for these accessorial modes of liability is necessary because while detailed elements for the substantive crimes within the jurisdiction of the Court were identified in the ‘Elements of Crimes’, no such elements were elaborated for the modes of liability in those crimes. The proposed elements in this volume break new ground and are designed to assist the ICC in applying the provisions of the Rome Statute to the cases before it for trial with consistency and accuracy.