Historians of China agree that the Chinese economy underwent a period of dramatic growth—some call it a commercial revolution—between AD 600 and 1400. As is so often the case, they have located all the causes within China: improved strains of rice, new technologies of water control, and the expansion of the market system. This book challenges the received wisdom by highlighting an important, but neglected, dimension of these economic changes: the effects of foreign trade on the city of Ch'üan-chou (also spelled Quanzhou).