Plato's Alcibiades I, the principle topic of which is self-knowledge, was held in great respect by Neoplatonist commentators and philosophers generally for over 2000 years before its authenticity came into question in the middle of the 19th century. Recent commentary on the topic of self-knowledge in Plato has, for the most part, allowed suspicions of inauthenticity to diminish the importance of this dialogue and its contribution to our understanding of self-knowledge in Platonic philosophy. The goal of this dissertation is twofold: first, it seeks to rehabilitate the Alcibiades I by arguing that it, and it alone, provides us with the clearest picture of self-knowledge in the Platonic corpus. Secondly, it argues that self knowledge, understood in the Alcibiades I as the acknowledgment of oneself as soul, is the foundation for philosophical thinking and knowing in Platonic philosophy. In chapter I, I show how Socrates brings Alcibiades to admit that he does not know what he claims to know, not for the sake of simply leaving him confused but insofar as this is the first step towards reorienting him towards acknowledging a different ground for knowing and living more generally. In chapter II, Socrates is seen to continue his elenchus with Alcibiades, showing him that the kind of education he has received is insufficient and that, in its place, he must seek an education that begins with an inquiry into what he is as a human being; in short, Alcibiades must know himself. Socrates then proceeds, as I show in chapter III, to undermine fundamental epistemological assumptions common to both Alcibiades and the Many for the purpose of bringing Alcibiades to acknowledge himself as a soul, which is seen to be the activity of self-determination. Through a discussion of Socratic love, Socratic self-determination is developed in chapter IV in opposition to a comportment that serves as the foundation not only for knowing but for living more generally. Finally, in chapter V, I show how Socrates argues that the acknowledgment of oneself as soul and the possibility of caring for oneself as such through self-determination is rooted in the soul's very structure, a structure that makes it possible for human beings to determine themselves as formable or changeable by seeing themselves as images of their determining capacity. I conclude by arguing that this ability to determine oneself by seeing oneself as an image requires the same kind of vision that is required for philosophical knowing. Accordingly, for Plato, before we come to know anything, we must first come to know ourselves.