The book argues that the theological motifs in Stoic philosophy are pivotal to our understanding of Stoic ethics. Part One offers an introductory overview of the religious world view of the Stoics. Part Two examines the Stoic characterizations of virtue and the virtues. Part Three deals with Stoic theories of how human beings can become virtuous. Part Four studies the practices of Stoic ethics. It shows inter alia how the Chrysippean table of virtues is still an (unacknowledged) influence behind Panaetius’ matrix of kathekonta, but how little agreement on the practical implications of their virtue ethics the Stoics could reach. The book suggests that the identity over time and cohesion of the Stoic school depended less on a commitment to the school founder’s memory and writings than on a common core of shared theological principles.