This article is devoted to the philosophical fragment found in 1977 in the Bactrian city of Aï Khanum. Both its content and origin are still a matter of dispute among scholars. I provide first a new edition of the three remaining columns of the fragment, based on a new reading of its photographic reproductions. The second part of this paper deals with the difficult problem of its origin. I give new evidence in favour of the hypothesis according to which the (...) transmitted text is a piece of the second book of Aristotle’s lost dialogue Περὶ φιλοσοφίας. First, the comparison between this fragment and the opening lines of Theophrastus’ so-calledMetaphysicssuggests that both of them were written shortly after Plato’s death in the same historical and philosophical context, viz inside the Assos circle. Then, I examine the hypothesis of Louis Robert and Paul Bernard according to which an epigram written at the end of a list of Delphic maxims also found in Aï Khanum must be attributed to Clearchus of Soli, the pupil of Aristotle during the Assos period. The close connection between Clearchus’ main philosophical interests and the first book of Aristotle’s lost dialogue explains why he chose to bring it with him during his journey through the East, and left it in Aï Khanum. Finally, the reconstruction of the general structure of the Περὶ φιλοσοφίας leads to the conclusion that the fragment must come from its second book. (shrink)