This is the editio princeps of the first major scholastic commentary on Aristotle'sMetaphysics, edited with features that make the work accessible. A doctrinal index summarizes many of Rufus' principal theses. An index to all the works cited by Rufus includes his many references to Averroes, whom Rufus regarded as his principal guide to the literal meaning of the text. The index generalis lists the principal questions in which Rufus states his more original positions. The extensive footnotes include many references to Rufus' predecessors and contemporaries, which allows readers to contextualize Rufus' interpretation. Finally, the introductions discuss some technical issues and introduce the reader to a few important topics in Rufus' philosophy.