Over the past decade, the Banking Union has reshaped the European Union's approach to banking oversight, creating a stronger and more resilient financial system. At its core, this landmark initiative established the European Central Bank (ECB) as the primary supervisor for Banking Union bank areas, introduced a robust resolution regime, and enhanced stability across the sector. This edited volume offers a comprehensive examination of the Banking Union's legal framework and its ongoing evolution. It addresses pressing questions about governance, accountability, and reform through a multi-dimensional lens, exploring six key areas: horizontal, substantive, institutional, cooperative, review, and external dimensions. The horizontal aspect addresses EU competences, soft law, fundamental rights, and inter-institutional relations. The substantive dimension focuses on the application of national law by the ECB, deposit guarantee schemes, and prudential supervision. Structural considerations focus on new frameworks and their powers, including the European Stability Mechanism and the emerging Anti-Money Laundering Authority. Cooperation is highlighted through EU-national collaboration, composite procedures, and state aid in banking. Oversight is examined via accountability mechanisms, judicial review, and litigation before the Court of Justice of the EU. Finally, external aspects explore the Banking Union's ties with non-eurozone members, EEA countries and Switzerland,By combining theoretical insights with practical analysis, EU Banking Union provides an original and in-depth understanding of the Banking Union's development, its complex legal architecture, and the challenges that lie ahead.