In his early lecture courses, delivered at the University of Freiburg and the University of Marburg from 1919 to 1928, Martin Heidegger exhibited an abiding interest in human life. Focusing on the facticity of living and speaking in the early lecture courses, this book traces the development of Heidegger's ideas about factical life through his interest in Greek thought and its concern with Being. Heidegger's existential concerns about human life and his ontological concerns about the meaning of Being crystallize in the notion of Dasein in Being and Time. Dasein is the Being of factical human life. Primarily through an examination of these early lecture courses, this book investigates the interconnected relationships human life has to science, religion, history, phenomenology, hermeneutics, and ontology, as well as language, sophistry, and rhetoric in the work of Plato and Aristotle. With an emphasis on the positive aspects of everydayness, this book explores the contexts of meaning embedded within life; the intensity of average, everyday life; the temporal immediacy of life in early Christianity; the hermeneutic pursuit of life's self-alienation; factical spatiality; the temporalizing of history within life; the richness of the world; and the facticity of speaking in Plato and Aristotle.