Aristotle (384 BC – 322 BC) was a Greek philosopher, a student of Plato and teacher of Alexander the Great. He wrote on many different subjects, including physics, metaphysics, poetry, theater, music, logic, rhetoric, politics, government, ethics, biology and zoology.

Aristotle (together with Plato and Socrates, Plato's teacher) is one of the most important founding figures in Western philosophy. He was the first to create a comprehensive system of philosophy, encompassing morality and aesthetics, logic and science, politics and metaphysics. Aristotle's views on the physical sciences profoundly shaped medieval scholarship, and their influence extended well into the Renaissance, although they were ultimately replaced by modern physics. In the biological sciences, some of his observations were only confirmed to be accurate in the nineteenth century. His works contain the earliest known formal study of logic, which were incorporated in the late nineteenth century into modern formal logic. In metaphysics, Aristotelianism had a profound influence on philosophical and theological thinking in the Islamic and Jewish traditions in the Middle Ages, and it continues to influence Christian theology, especially Eastern Orthodox theology, and the scholastic tradition of the Roman Catholic Church. All aspects of Aristotle's philosophy continue to be the object of active academic study today.

Though Aristotle wrote many elegant treatises and dialogues (Cicero described his literary style as "a river of gold"), it is thought that the majority of his writings are now lost; it is believed that only about one third of the original works have survived.