This volume is concerned with the religious, social and commercial 'networking' methods extending over a large part of the world, ranging from the Near East to South America, used by the western Sephardic Jewish diaspora - and the linked 'New Christian' diaspora (in lands where the Inquisition prevailed)- from the mid sixteenth to the mid eighteenth century. Particular attention is given to the role of these unique diasporas in the functioning of the six great European world maritime empires of the time - the Venetian, Spanish, Portuguese, Dutch, English and French. New material and argument is offered relating to the questions of diaspora formation, Sephardic social practices, crypto-Judaism, religious syncretism, cross-cultural brokerage, and the contribution of diasporas to European expansion.