This scientific monograph addresses scholars, students, and practitioners in EU law by examining a fundamental question: does the European Public Prosecutor's Office represent a threat to the Rule of Law or a new instrument for safeguarding it? Through institutional analysis of the Rule of Law and historical study of European criminal law institutions, the book demonstrates that EPPO is the next step in the progression of Rule of Law guarantees. Beyond repressing transnational fraud, EPPO's mission is inextricably linked to protecting the Rule of Law by defending citizens' rights. Analysing practical cases across five macro-areas, health, culture, environmental sustainability, legal economy, and better future, the book shows how protecting the Union's financial interests simultaneously protects fundamental rights. The answer is clear: EPPO does not threaten the Rule of Law but strengthens it.