A student of Plato and a teacher of Alexander the Great, Aristotle is one of the towering figures in Western thought. A brilliant thinker with wide-ranging interests, he wrote important works in physics, biology, poetry, politics, morality, metaphysics, and ethics. The Ethics of Aristotle is one half of a single treatise of which his Politics is the other half. Both deal with one and the same subject. This subject is what Aristotle calls in one place the 'philosophy of human affairs;' but more frequently Political or Social Science. In the two works taken together we have their author's whole theory of human conduct or practical activity, that is, of all human activity which is not directed merely to knowledge or truth. The two parts of this treatise are mutually complementary, but in a literary sense each is independent and self-contained. Aristotle's work has had a lasting influence on all subsequent Western thought about ethical matters.