Gregory Akindynos (died ca. 1348) was one of the main protagonists in the Byzantine Hesychast Controversy. A fellow student and friend of Gregory Palamas, he became the main opponent of the Palamite teaching about the divine energies in the course of 1341. The essays collected in this volume examine the role Akindynos played as a former friend and later adversary of Palamas, as an ecclesiastical authority at the court of Constantinople, as an author and a theological opponent of the doctrine of the uncreated energies of God. The collected papers address these issues from philological, historical, philosophical, and theological perspectives and contribute to a better understanding of Akindynos and his role in the history of the Hesychast Controversy.