The thirteenth volume based on the Giorgio Levi Della Vida conference reassesses the role of the Iranian peoples in the development and consolidation of Islamic civilization. In his key essay, Ehsan Yarshater casts fresh light on that role challenging the view that, after reaching a climax in Baghdad in the ninth century, Islamic culture entered a period of decline. In fact, he maintains, a new and remarkably creative phase began in Khurasan and Transoxania, symbolized by the adoption of Persian as a medium of literary expression. By the mid-sixteenth century, Persian literary and intellectual paradigms had spread from Anatolia to India, encompassing the greater part of the Islamic world. Yarshater also challenges traditional assumptions about the 'Islamization of Persia'. In the essays which follow, six distinguished scholars consider the historical, cultural, and religious aspects of the Persian presence in the Islamic world.