The principal aim of the Rome Statute of the International Criminal Court is to end impunity for the "most serious crimes of concern to the international community" through a commitment to the retributive and deterrent functions of international accountability. Admissibility in the Rome Statute of the International Criminal Court examines the model of complementary accountability created by the Rome Statute. It investigates the two arms of admissibility that underpin the jurisdiction of the Court: complementarity and gravity. The first condition requires that the alleged crimes reach a certain level of gravity and seriousness, and the second that none of the states that have jurisdiction over the crimes are willing or able to prosecute the alleged perpetrators. The book assesses whether the organs of the Court, principally the Office of the Prosecutor, have interpreted and applied the admissibility provisions in accordance with the Rome Statute, and in a way that maximises its object and purpose.

In assessing the complementarity and gravity arms of admissibility, the book considers the interrelationship between the two. It argues that the interpretation and application of the two arms of admissibility by the organs of the Court create a situation in which they each reinforce the other, creating a model of accountability which differs in some important respects from the drafters' vision. It concludes that this may be the inevitable result of a new institution struggling to manage the divergent tensions and expectations which underlie and complicate its enterprise, but it may also serve to impede the realisation of the Statute's key objectives.