Every currency crisis of recent years has been accompanied by a migration of billions of short-term money. Both experts and laymen have again and again been amazed at the speed at which, at relatively short notice, these enormous sums could be mobilised.

A widely spread belief among economists is that monetary policy has relatively short-lived effects on real variables such as unemployment. Previous studies indicate that monetary policy affects the output gap only at business cycle frequencies, but the effects on unemployment may well be more...