Early versions of some of the material in this book were delivered as papers in Cambridge, Charlottesville, Helsinki, Jerusalem, Oxford, Princeton, Salamanca and Yale, and published in volumes edited by Leofranc Holford-Strevens and Amiel Vardi, José-Antonio Fernández Delgado and Antonio Stramaglia. Warmest thanks are due to the participants in all those seminars and conferences for their lively discussion of ideas and helpful suggestions.

Various chapters were kindly read in draft by David Charles, Anna Clark, Alison Cooley, Miriam Griffin, Robert Kaster, Geoffrey Lloyd, Katerina Oikonomopoulou and Malcolm Schofield. Between them they suggested numerous improvements and saved me from many mistakes. Malcolm Schofield transformed my understanding of what it meant to be a philosopher in the early Roman Empire, for which I am especially grateful.

Many Oxford colleagues have contributed to the project in informal conversations, and it is a continuing pleasure to work among so many stimulating colleagues. Among those with whom, internationally, it is a pleasure to share an interest in ethics are Catalina Balmaceda and the economist Vivien Foster, who over the years has made me think harder and more constructively about more topics than anyone else.

Wishing the book to be accessible to those without Greek and Latin, I have translated primary sources throughout. Unfortunately, to include the many thousands of texts cited in the original as well would have made the text hopelessly bulky, so with considerable regret, they are omitted.