What is the optimal number of currencies in the world? Common currencies affect trading costs and, thereby, the amounts of trade, output, and consumption. From the perspective of monetary policy, the adoption of another country's currency trades off the benefits of commitment to price stability...

The last decade has witnessed an explosion in the number of regional trade agreements (RTAs). There seems to be a general if ill-defined belief on the part of many policy-makers, and among a number of academics as well, that there is more to a RTA than the traditional gains from trade. This...