This book is the first systematic study of Descartes' relationship to Augustine. It offers a complete reevaluation of Descartes' thought and as such will be of major importance to all historians of medieval, neo-Platonic, or early modern philosophy. Special features include a reading of the Meditations, a comprehensive historical and philosophical introduction to Augustine's thought, a detailed account of Plotinus, and a contextualization of Descartes' mature philosophical project.