The European Central Bank (ECB) was first introduced in the European legal order on the occasion of the Treaty of Maastricht (1992). An official EU institution which is governed by EU law, the ECB of modern times differs vastly from its inception in 1998, which manifests in three main ways: monetary policy options, consideration of concerns other than low inflation in its policy-making, and its role in the Banking Union. This edited collection offers a retrospective and prospective account of the ECB, charting its evolution in detail with chapters written by leading academics and practitioners. Part 1 examines the substantive changes to monetary policy introduced by the ECB as a consequence of the financial and sovereign debt crisis by considering their legal basis. Part 2 moves beyond monetary policy by shifting to the new roles that the ECB has been called upon to play, notably in banking supervision and resolution. Parts 3 and 4 deal with transformations to inter- and intra-institutional relations, and take stock of these transformations, reflecting on the nature of the ECB of current times and which direction it could be heading in the future. The authors analyse the most salient and controversial elements of the ECB's crisis response, including unconventional monetary policy measures and the ECB's risk management strategy. Beyond monetary policy, the book further examines the role played by objectives such as financial stability and environmental sustainability, the ECB's relationship to the Lender of Last Resort function, as well as its new responsibilities in the Banking Union.