A generation of great international economists is passing from the scene. Richard Cooper died on 23 December, Robert Mundell on 4 April, and John Williamson on 11 April 2021. All three made important contributions on a variety of topics, and coined memorable terms that remain in use, though not always in their originally intended sense. More specifically, all three played a role in the ongoing debate about optimal currency arrangements. Each was unhappy with the system of market-determined floating exchange rates and proposed reforms. Should central banks fix exchange rates,...