From Iamblichus to Eriugena was completed almost fifty years ago and, having been in considerable demand but out of print for many years, is here made available once more without substantial alteration. The original book described the metaphysical and theological system of later (post-Plotinian) Neoplatonism in one of its most important pagan forms and in one of its most significant Christian forms, and especially strove to depict the conceptual analogies and doctrinal intersections between these two often competing sets of ideas. Above all, it attempted to trace a historical evolution of philosophy and pass through what can only be characterized as a labyrinth, making sure to follow one continuous path towards its exit while avoiding too many false detours. Beginning the survey with Iamblichus of Chalcis in Graeco-Roman Antiquity and ending with Iohannes Scottus Eriugena in the later Carolingian Era, it posited two pagan Neoplatonists, Proclus and Damascius, and two Christian theologians, pseudo-Dionysius the Areopagite and Maximus the Confessor, as the most crucial historical intermediates. It was the shared methodologies of this group of authors that, despite the opposition inherent in their religious affiliations, provided the ground-plan for the historical narrative developed in this book.

The reprint of this book includes a new introduction which is intended to be a substantial document in its own right for at least two reasons. First, it provides a meta-critical analysis of historical and conceptual method pursued in the original work especially by drawing the reader’s attention to ideas, topics, and themes that were mentioned but given less emphasis in the earlier text. The shift of focus is in response to published critiques of the original book as well as to independent developments in the relevant scholarship during the last fifty years. Second, the new introduction provides bibliographical notices of the present author’s numerous more recent publications dealing with the same or similar issues. These publications generally reinforce the conclusions of the earlier work with the accumulation of fresh evidence. In certain cases, the new material takes on a genuinely supplemental role by filling hermeneutical gaps in the earlier narrative. Finally, the reprint of this book includes a new and expanded bibliography which, especially with respect to primary sources, provides a thorough survey of recent scholarly work on the authors selected for the original discussion.