Tucker’s thoughtful disquisition on democracy in modern societies focuses on the relationships between citizens and various branches of the state. The last quarter of the book covers the structure of independent central banks and how much authority should be delegated to them—in normal times and in emergencies, such as the financial crisis of 2007–8. Tucker draws heavily on the history of the Bank of England, where he worked as a regulator for 30 years, but he also discusses other central banks, including the U.S. Federal Reserve and the European Central Bank. In Tucker’s view, to retain legitimacy and credibility, independent agencies must operate transparently and must enjoy clearly defined powers. For central banks, these involve setting monetary policy, regulating and supervising the banking system, serving as the lender of last resort, and carrying out some less common policies in emergencies, such as quantitative easing. Tucker’s work is full of valuable insights for central bankers as well as their critics.