Nicomachean Ethics

The Nicomachean Ethics is the central treatise of Aristotle's moral philosophy and one of the foundational books of Western thought. Composed in the 320s BCE — probably as lecture notes at the Lyceum — it survives in ten books that work, with extraordinary patience, through the question of what makes a human life go well.

Aristotle's answer is eudaimonia: the flourishing life, the life of activity in accordance with virtue. The middle books work through the moral virtues and arrive at the famous doctrine of the mean: that virtue lies between two corresponding vices of excess and deficit. The closing books turn to friendship — treated more profoundly than in almost any later text — and to the contemplative life as the highest form of human flourishing.