This is a seminal study of the economic history of the Jewish community of Aragon, covering a period of about 125 years from the beginning of the thirteenth century until 1327. Among other topics, the book deals with the policy of the Crown towards moneylending and commerce in the Jewish community; the community's control over its members' economic activities; the Jews' loans to the king, and their taxes and subsidies to the Crown. The book offers information on the Jews' contribution to economic history, that has been very little studied so far. It will be of interest to economic historians, historians of Jewish Middle Ages, hispanists, and medievalists in general.