This book investigates the discretionary powers of the Prosecutor of the International Criminal Court and the boundaries to his discretion. These boundaries come first of all from the reviewing powers of the Chambers, but also from the control exercised by other subjects, such as States, the UN Security Council and the Assembly of the States Parties to the Rome Statute. Although from concepts such as ›gravity‹ and ›interests of justice‹ it might be inferred that the Prosecutor benefits from broad discretion, an in-depth analysis of these concepts, in conjunction with an investigation on the judicial reviewing powers of the Chambers at the investigation stage and in the confirmation of the charges proceedings, suggest that the Prosecutor’s discretion should not be overestimated.