http://en.wikipedia.org/wiki/Nicomachean_Ethics

The Nicomachean Ethics (/nɪˌkɒmæˈkiːən/) is the name normally given to Aristotle’s best-known work onethics. The work, which plays a pre-eminent role in defining Aristotelian ethics, consists of ten books, originally separate scrolls, and is understood to be based on notes from his lectures at the Lyceum.

The theme of the work is the Socratic question which had previously been explored in Plato’s works, of how men should best live. In his Metaphysics, Aristotle described how Socrates turned philosophy to human questions, whereas Pre-Socratic philosophy had only been theoretical.

http://www.sparknotes.com/philosophy/ethics/summary.html

All human activities aim at some end that we consider good. Most activities are a means to a higher end. The highest human good, then, is that activity that is an end in itself. That good is happiness. When we aim at happiness, we do so for its own sake, not because happiness helps us realize some other end. The goal of the Ethics is to determine how best to achieve happiness. This study is necessarily imprecise, since so much depends on particular circumstances.

Happiness depends on living in accordance with appropriate virtues. Virtue is a disposition rather than an activity. That is, a virtuous person is naturally disposed to behave in the right ways and for the right reasons, and to feel pleasure in behaving rightly.   …

One by one, Aristotle discusses the various moral virtues and their corresponding vices. Courage consists of confidence in the face of fear. Temperance consists of not giving in too easily to the pleasures of physical sensation. Liberality and magnificence consist of giving away varying amounts of money in appropriate and tasteful ways. Magnanimity and proper ambition consist of having the right disposition toward honor and knowing what is one’s due. Patience is the appropriate disposition toward anger, though it is sometimes appropriate to show some degree of anger. The three social virtues of amiability, sincerity, and wit make for pleasant and engaging interaction with others. Modesty is not properly a virtue, but an appropriate disposition toward shame, which is admirable in the young. Justice in a sense encompasses all the other virtues, since being just consists of exhibiting virtue generally.

While the moral virtues dispose us to behave in the correct manner, it is necessary also to have the right intellectual virtues in order to reason properly about how to behave. There are five intellectual virtues. Three of them—scientific knowledge, intuition, and wisdom—consist of contemplative reasoning, which is detached from human affairs. The other two—art or technical skill and prudence—consist of calculative reasoning, which helps us make our way in the world. Prudence is the intellectual virtue that helps us reason properly about ethical matters.