Theodore Metochites' Aristotelian paraphrases (c. 1312), covering all 40 books of the Stagirite's extant works on natural philosophy, constitute one of the major achievements of late Byzantine learning. This volume offers the first critical edition of Metochites' paraphrases of the three books of the De anima, accompanied by an introduction and an English translation with an apparatus of parallel passages in Aristotle's ancient commentators. The first part of the introduction presents and evaluates the sources for the text, consisting of thirteen Greek manuscripts, a 15th-century Greek epitome and a 16th-century Latin translation. The genealogical relationships between these are established on the basis of separative and conjunctive errors, identified, inter alia, through critical discussions of more than 300 passages. The second part of the introduction discusses the nature, purpose and sources of the paraphrases as well as several linguistic questions with implications for editing and translating the text. The third part of the introduction sets out the principles of this edition and translation.