||This dissertation interrogates the notions of selfhood, agency, and subjectivity in the autobiographical works of Jean-Paul Sartre, Friedrich Nietzsche, Søren (Soren) Kierkegaard, and Jacques Derrida, all of which are significantly under-researched in the philosophical literature. I show, in each case, that the autobiographical works have a significant philosophical core that deserves drawing out, particularly with relevance to the knot of problems surrounding the quaestio mihi factus sum --the question, enigma, or mystery that I am. I situate each work within the context of the author's larger treatment of the same issues in the more "theoretical" works, and then proceed to show that the autobiographical works all present a slightly different or more advanced picture of things, which is in each case at least partially dependent upon the genre itself. In the case of Sartre, this amounts to a real balance between freedom and the force of circumstances in Les Mots (Words) ; for Nietzsche, the virtual effacement of all conscious activity in Ecce Homo . For Kierkegaard and Derrida, the primary difference is performative: they are doing something in their autobiographical texts that they are not elsewhere. Kierkegaard's On My Work as an Author is, as he says, a "deed" rather than a "work"; likewise, Derrida's Circonfession (Circumfession) is an attempt to enact an "event." I further establish that there is a veritatem facere , a "making," "doing," or "performing" of the truth, in each autobiographical text--in the form of an integration of our past into our current situation (Sartre), an affirming of our fate (Nietzsche), a witnessing before God (Kierkegaard), and a testifying to our responsibility to the Other (Derrida). I conclude by reflecting on some of the more significant successes, failures, and problems inherent in these autobiographical projects, in light of philosophical reflection on the genre.