"The Nicomachean Ethics" (in Greek: Ἠθικὰ Νικομάχεια, transl. Ēthicà Nicomácheia; in Latin: Ethica Nicomachea) is Aristotle's principal work on ethics. In it, he presents his teleological and eudaimonistic conception of practical rationality, his understanding of virtue as the mean, and his considerations on the role of habit and prudence.

For Aristotle, all practical rationality is teleological, meaning it is oriented toward an end (or a good, as the text states). Ethics is tasked with determining the highest end (the *summum bonum*) that presides over and justifies all others and identifying the way to achieve it.

This highest end is happiness (*eudaimonia*), which consists not in pleasures, wealth, or honors, but in a virtuous life. Virtue, in turn, lies in the "golden mean" between extremes, to be found by the person endowed with prudence (*phronesis*) and trained in its practice through habit.

It is important to note that the concept of virtue in Ancient Greece differs from the modern sense, heavily influenced by Christianity. Virtue referred to the excellence of each action—doing each act well and in the right measure. Additionally, the values of the time and place in which Aristotle wrote were very different from those of modern readers; terms such as "good" or "bad" held entirely different meanings. For instance, servitude and male dominance were viewed as natural in his era, though they have since come to be seen as "bad" due to post-Christian values.