The Nicomachean Ethics
Aristotle (384-322BC) is the philosopher who has most influence on the development of western culture, writing on a wide variety of subjects including the natural sciences as well as the more strictly philosophical topics of logic, metaphysics and ethics. To the poet Dante, he was simply 'the master of those who know'.
The Ethics contains his views on what makes a good human life. While the work continues to stimulate and challenge modern philosophers, the general course of the argument is easily accessible to the non-specialist. Both as a key influence in the history of ideas and as a work containing unique insights into the human condition, this is a book that simply demands to be read.