The book includes seven studies that use historiographical and philological methods to explore the historical and religious aspects of Zoroastrian cosmogony and eschatology. It undertakes a close reading of Middle Persian literature to identify and illustrate specific aspects of this religious system, such as the symmetry between the beginning and the end of the world. The author reads the historiography of Iranian studies, paying special attention to the French scholarship on this topic, in order to show how the modern history of religions transformed Christian theological concepts in its analysis of the Zoroastrian religion. The Addenda include several unpublished documents, relevant for the history of Zoroastrian studies in France.