How does Plato view his philosophical antecedents? Plato and his Predecessors considers how Plato represents his philosophical predecessors in a late quartet of dialogues: the Theaetetus, the Sophist, the Politicus and the Philebus. Why is it that the sophist Protagoras, or the monist Parmenides, or the advocate of flux, Heraclitus, are so important in these dialogues? And why are they represented as such shadowy figures, barely present at their own refutations? The explanation, the author argues, is a complex one involving both the reflective relation between Plato's dramatic technique and his philosophical purposes, and the very nature of his late philosophical views. For in these encounters with his predecessors we see Plato develop a new account of the principles of reason, against those who would deny them, and forge a fresh view of the best life - the life of the philosopher.