John Palmer presents a new and original account of Plato's uses and understanding of his most important Presocratic predecessor, Parmenides. Adopting an innovative approach to the appraisal of intellectual influence, Palmer first explores the Eleatic underpinnings of central elements in Plato's middle-period epistemology and metaphysics. He then shows how in the later dialogues Plato confronts various sophistic appropriations of Parmenides while simultaneously developing his own deepened understanding. Along the way Palmer gives fresh readings of Parmenides' poem in the light of the Platonic reception, and discusses Plato's view of Parmenides' relation to such key figures as Xenophanes, Zeno, and Gorgias. By tracing connections among the uses of Parmenides over the course of several dialogues, Palmer both demonstrates his fundamental importance to the development of Plato's thought and furthers understanding of central problems in Plato's own philosophy.