In the seventeenth century, Amsterdam took in several thousand New Christians from the Iberian peninsula, descendants of Jews who had been forcibly baptized some two hundred years earlier. Shortly after their initial settlement, the members of this mostly Portuguese refugee community chose to manifest themselves as Jews again. No real obstacles were put in their way. The tolerance extended to them by the Amsterdam authorities was as exemplary as their new-found commitment to Jewish orthodoxy (barring a few famous instances) was strong. These circumstances engendered the new dynamic of a traditional Jewish society creatively engaged with the non-Jewish, secular world in relative harmony. Amsterdam's Portuguese Jewry was in this sense the first modern Jewish community. Through a fresh and rigorous approach to the documents, Daniel Swetschinki's lively and original portrait of this justly famous community presents some unexpected conclusions. As well as characterizing the major dimensions of the New Christian migrations and identifying trends within an array of economic activities, it explores the appeal that Judaism exercised as a religion and as a communal structure. Throughout, the analysis focuses on the common rather than the exceptional and seeks the centre from which the interrelationship of all the constituent parts may be grasped. Swetschinski's emphasis is on the social dimension of Portuguese Jewish economic and religious life, formal and informal. He thereby uncovers the internal dynamics of this remarkable Jewish community that moulded a renegade New Christian population into a model Jewish society, 'model' in the sense that it had the support of proponents of modernity and traditionalism alike and also won the respect of the Christian population. His research adds a broad and authentic vision to the panoply of images of early modern Jewish history and enables him to offer new insights into the troublesome question of the transition from medieval to modern Judaism.