This volume contains the first edition of the Latin version of the Middle Commentary of Averroes on Aristotle's Nicomachean Ethics Book X, the original arabic version being lost. It is accompanied by an annotated French translation. The volume also contains a full study of the manuscript tradition of the Latin text and sets outs the principles used in the edition, which takes into account, where necessary, the Hebrew version of the Commentary. Two further studies complete the volume: the first is devoted to the genre of "Middle Commentary" (talhis); the second considers how Averroes uses an analogy with medicine to place ethics at the heart of practical philosophy, and how, in a manner that is foreign to Aristotle, he conceives of ethics as a "science." Ce volume propose la toute premiere edition, accompagnee d'une traduction francaise annotee, de la version latine du Commentaire moyen d'Averroes a l'Ethique a Nicomaque d'Aristote Livre X, dont l'original arabe est perdu. Il presente egalement une etude complete de la tradition manuscrite du texte latin, et les principes d'edition, qui prennent en compte, ponctuellement, la version hebraique du Commentaire. Deux etudes viennent completer ce volume: l'une, consacree a la notion de "commentaire moyen" (talhis), l'autre a la place qu'Averroes - par le biais d'une analogie avec la medecine - reserve a l'ethique au sein de la philosophie pratique, et a la facon dont il concoit desormais, de facon non aristotelicienne, l'ethique comme une "science."