This chapter examines the tension in classical thought between reciprocity and altruism as the two fundamental grounds of interpersonal relations within the city and, to a lesser extent, between citizens and foreigners. It summarizes the chapters that follow, and examines in particular the ideas of altruism and egoism and defends their application to ancient ethics. Various attempts to reconcile the two, especially in respect to Aristotle’s conception of virtue as other-regarding, are considered, and with the relationship to modern concepts of “egoism” and “altruism” is explored. The introduction concludes by noting that one of the premises of the book is that, in classical antiquity, love was deemed to play a larger role in the way people accounted for motivation in a number of domains, including friendship, loyalty, gratitude, grief, and civic harmony.