This chapter explains the thorny issue of Ecnomic Monetary Union (EMU), which is a feature that frequently absent from comparable texts. The process of EMU is, for example, merely a step along a theoretical road in terms of exchange rate regimes. It reviews the development of adopted exchange rate regimes by Britain since the Gold Standard of the 19th century and in particular summarises the arguments concerning the polar extremes of fixed and floating systems. The European Exchange Rate Mechanism (ERM) of the European Monetary System (EMS) was a distinct shift back to less flexible exchange rates between the participating countries. Moreover, the continuation along this path to EMU entailed the disappearance of exchange rates between EMU members altogether as a single currency is adopted for use. Looking towards the prospect of EMU itself, a similar cost-benefit calculation is required by potential participating member states.