The Regulation on the establishment of the European Public Prosecutor's Office (EPPO) provides the legal framework for an entirely new Union body with the power to investigate and prosecute criminal offences affecting the financial interests of the Union. Starting its operational work on 1 June 2021, the EPPO will be an additional and powerful player in at least 22 national criminal justice systems, working closely together with national law enforcement authorities and exercising the functions of prosecutor in the competent courts of the Member States. The Commentary on the EPPO Regulation is intended to guide practitioners - within EPPO as well as in the national prosecution services and law enforcement agencies, courts, and law offices - in the interpretation of the Regulation. By providing an in-depth analysis of the intricate interplay of the Regulation's provisions and their legal and practical context, it will also provide a valuable source for further academic research on individual aspects relating to the EPPO. In addition, the Commentary will assist political decision-makers in assessing the practical implementation of the EPPO Regulation by clarifying its relations to national law and national judicial and law enforcement authorities.