Phenomenological Interpretations of Aristotle, the text of a lecture course presented at the University of Freiburg in the winter of 1921-1922, was first published in 1985 as volume 61 of Heidegger's collected works. Preceding Being and Time, the work shows the young Heidegger introducing novel vocabulary as he searches for his genuine philosophical voice. Here, Heidegger first takes up the role of the definition of philosophy and then elaborates a unique analysis of "factical life," or human life as it is lived concretely in relation to the world, a relation he calls "caring." Heidegger's descriptions of the movement of life are original, striking, and unique to this lecture course. As he works out a phenomenology of factical life, Heidegger lays the groundwork for a phenomenological interpretation of Aristotle, whose influence on Heidegger's philosophy was pivotal. Important and detailed discussions of phenomenological research, philosophical definition, formal indication, the relationship between philosophy and the sciences, facticity, the surrounding world, questionability, and temporality emerge from this provocative text. As an early articulation of Heidegger's thought, this book is an indispensable resource for scholars and students.