The essays in this book discuss a number of the central metaphysical and ethical themes that engaged the minds of Platonist philosophers during late Antiquity and the early Middle Ages. One particular theme is that of the structure of reality, with the associated questions of the relations between soul and body and between intelligible and sensible reality, and the existence of mathematical objects. Other topics relate to evil and beauty, political life and its purpose, the philosophical search for the absolute Good, and how one can speak about this Absolute and have union with it. Going from Plato to Eriugena, the ways in which Platonist philosophers understood and developed these themes are analysed and compared.