This monograph has its origins in a Cambridge Ph. D. dissertation di- rected by Geoffrey S. Kirk and Patricia E. Easterling, and examined by Nicholas J. Richardson and Frank H. Stubbings. The body of the work has since been revised, and the Introduction and the first two and last chapters have been added. A grant from the Office of the Vice President for Academic Affairs at Davidson College enabled me to prepare a camera- ready copy with the secretarial assistance of Cheryl Branz and the expert advice of John Heil in the Philosophy Department. I want to extend appre- ciation to my colleagues in the Department of Classical Studies, Dirk French and Michael K. Toumazou, for reading portions of the manuscript. It is a special pleasure to record my long-standing debt to Pat Easter- ling for maieutic gifts so freely bestowed then and now. To Richard Janko I must also express my deep gratitude for his continuing encouragement and for cheerful commentary on the manuscript both as a dissertation and as a monograph. Lowell Edmunds and S. Douglas Olson read and made insightful observations on the opening chapters. I am grateful to Hoyt Rogers, who, with attention to content and important detail, exercised acute editorial judgment, and in so doing helped smooth the prose. Ludwig Koe- nen’s circumspect questions and criticisms have proven valuable in preparing the final version of this work. Any errors or infelicities that re- main are mine alone.