This book argues that Plato's Charmides presents a unitary but incomplete argument intended to lead its readers to substantive philosophical insights. Through careful, contextually sensitive analysis of Plato's arguments concerning the virtue of sophrosyne, Thomas M. Tuozzo brings the dialogue's lines of inquiry together, carrying Plato's argument forward to a substantive conclusion. This innovative reading of Charmides reverses misconceptions about the dialogue that stemmed from an impoverished conception of Socratic elenchus and unquestioned acceptance of ancient historiography's demonization of Critias. It views Socratic argument as a tool intended to move its addressee to substantive philosophical insights. It also argues, on the basis of recent historical research, a review of the fragments of Critias' oeuvre and Plato's use of Critias in other dialogues, that Plato had a nuanced, generally positive view of Critias. Throughout, readers are alerted to textual difficulties whose proper resolution is crucial to understanding Plato's often abstract arguments.