The Discourses are a key source for ancient Stoicism, one of the richest and most influential schools of thought in Western philosophy. They not only represent the Stoicism of Epictetus' own time, but also reflect the teachings of such early Stoics as Zeno and Chrysippus, whose writings are largely lost. The first of the four books of the Discourses is philosophically the richest: it focuses primarily on ethics and moral psychology, but also touches on issues of logic, epistemology, science, and rhetoric. Other notable schools of ancient thought, including Epicureanism, the Sceptics, and the...