This publication deals with an anonymous Arabic paraphrase of Aristotle's "De Anima." The paraphrase, which was translated into Persian in the thirteenth century, is to be considered as the earliest testimony of Arabo-Islamic interest in Aristotelian psychology. The first part of the book is concerned with the Arabic and Persian manuscripts and testimonies, the Greek sources of Late Antiquity, and the question of the date and identity of the author. The second part includes a critical edition with a German translation followed by a philological and philosophical commentary in the fourth part....