This book presents Gregory of Nyssa's On the Six Days of Creation (In Hexaemeron) as a specimen of Early Christian philosophy. It comprises Gregory of Nyssa's text in its Greek original accompanied by a new English translation, and seven accompanying essays by international specialists from diverse backgrounds. Each essay focuses on a section of the text and the arising philosophical issues. The essays complement each other in offering multiple perspectives on how Gregory's text may be approached philosophically and positioned in relation to other, more or less contiguous, philosophical theories, including the early Greeks Anaxagoras and Empedocles, Aristotle, and the Stoics. Rather than presenting a definite and exhaustive state of the art study of Gregory's text, this volume aims to open new pathways for research into In Hexaemeron.