Through careful analysis of phenomenological texts by Husserl and Heidegger, Marion argues for the necessity of a third phenomenological reduction that concerns what is fully implied but left largely unthought by the phenomenologies of both Husserl and Heidegger: the unconditional "givenness" of the phenomenon. At once historically grounded and radically new, this phenomenology of givenness has revitalized phenomenological debate in Europe and the U.S.