Confounding forecasts of disruption and market turbulence, the transition to monetary union in Europe took place very smoothly. Some recent developments, however, are cause for concern, and important problems must still be resolved. The governments of most euro-zone countries do not subscribe to...

The emerging-market crises of the 1990s were characterized by crashes in exchange rates, credit flows, and output, and the currency crashes caused the other two. Because local banks and firms had large foreign-currency debts, the sharp depreciations of their countries' currencies had huge...