This study, completed in April 2024, aims at comprehensively presenting and thoroughly analysing the legal framework governing the definition and implementation of the single monetary policy in the euro area during the first twenty-five years of the Eurosystem’s operation. In this historical context, the focus is on the legal aspects pertaining to the definition and implementation of this single monetary policy since the establishment of the Eurosystem on 1 January 1999 amidst, and in response to, several financial and non-financial crises which erupted in the course of that period (and in particular since 2007, which marked the onset of the Global Financial Crisis). The ultimate goal is to highlight the significant contribution and the importance of the legal framework in shaping the single monetary policy of the Eurosystem, in normal times and at times of stress. The study is structured in two key chapters entitled “The Single Monetary Policy in the Euro Area: Definition and Legal Framework” and “Implementation of the Single Monetary Policy in the Euro Area in Periods of Crises”. The Epilogue (Chapter 3), entitled “Considerations on the Impact of Monetary Policy Decisions on Financial Stability in the Euro Area” discusses the interaction between monetary policy and financial stability, as well as the latest (until April 2024) financial stability conditions in the euro area through the lens of international and EU official reports, taking also into account the (spring 2023) banking turmoil.