The Nicomachean Ethics

The Nicomachean Ethics is Aristotle's best-known work on ethics: the science of the good for human life, that which is the goal or end at which all our actions aim.  It consists of ten sections, referred to as books, and is closely related to Aristotle's Eudemian Ethics. The work is essential for the interpretation of Aristotelian ethics.
The text centers upon the question of how to best live, a theme previously explored in the works of Plato, Aristotle's friend and teacher. In Aristotle's Metaphysics, he describes how Socrates, the friend and teacher of Plato, turned philosophy to human questions, whereas pre-Socratic philosophy had only been theoretical and concerned with natural science. Ethics, Aristotle claimed, is practical rather than theoretical, in the Aristotelian senses of these terms. It is not merely an investigation about what good consists of, but it aims to be of practical help in achieving the good.
It is connected to another of Aristotle's practical works, Politics, which reflects a similar goal: for people to become good, through the creation and maintenance of social institutions. Ethics is about how individuals should best live, while politics adopts the perspective of a law-giver, looking at the good of a whole community.