In his provocative American Economic Review paper “A Theory of Optimum Currency Areas,” Mundell argued that as long as workers could move within a currency region to where the jobs were, the region could afford to forgo the equilibrating mechanism of exchange-rate adjustment. He credited another (future) Nobel Prize winner, James Meade, for having recognized the importance of labor mobility in earlier work, but criticized Meade for interpreting the idea too stringently, especially in the context of Europe’s nascent integration.