ABSTRACTThe important role played by Aristotle in Martin Heidegger’s path towards Being and Time during the 1920's is now well documented. Yet an important chapter of this story remains mostly unexplored: Heidegger's early attempt to develop an ontology of life in dialogue with Aristotle. This is because the early seminars in which Heidegger developed his important and highly original interpretation of Aristotle's De Anima remain unpublished : one seminar from the summer of 1921 and one spanning the winter semester of (...) 1922/23 and the summer semester of 1923. In the present paper, I reconstruct Heidegger's key interpretative moves in the latter seminar on the basis of a detailed handwritten transcript preserved among the papers of his student Helene Weiss held at Stanford University. What emerges is a dialogue between Aristotle and Heidegger that enables us better to understand and to question the thought of both philosophers on the phenomenon of life. (shrink)