Aspasius' commentary on the "Nicomachean Ethics", of which six books have come down to us, is the oldest surviving Greek commentary on any of Aristotle's works, dating to the middle of the second century AD. It offers precious insight into the thinking and pedagogical methods of the Peripatetic school in the early Roman Empire, and provides illuminating discussions of numerous technical points in Aristotle's treatise, along with valuable excursuses on such topics as the nature of the emotions. This is the first complete translation of Aspasius' work in any modern language.