My dissertation examines Heidegger's phenomenology of estrangement and responsibility. I argue that one of the central issues of Being and Time is the possibility of an estranged individual's transformation into a responsible self. For Heidegger, each agent's original condition is one of estrangement—or a failure to be oneself—because socialization, although a necessary condition of agency, often encourages integration at the expense of self-determination. Estrangement thus involves being held at a distance from one's autonomy, and one can overcome this condition and become a self only by making the inward movement to ‘be-responsible’ or ‘resolute’. Pace Heidegger's critics, then, I show that resoluteness does not represent a bare valorization of the will but rather a way of life that involves, at the very least, satisfying the following four criteria: (1) delimiting the sphere of action for which I can be held accountable, (2) taking responsibility for my decisions and the standards in light of which I make them, (3) sustaining the commitments that are definitive of my identity and thereby preserving my integrity, and (4) carrying out my existence with an ethical regard towards the freedom of those upon whom my own capacity to act depends.