Along with Socrates and Plato, Aristotle was one of the most influential of the ancient Greek philosophers. They transformed Presocratic Greek philosophy into the foundations of Western philosophy as we know it. Some consider Plato and Aristotle to have founded two of the most important schools of Ancient philosophy; others consider Aristotelianism as a development and concretization of Plato's insights.

Aristotle was born in Stageira in Chalcidice. His parents were Phaestis and Nicomachus, who became physician to King Amyntas of Macedon. Aristotle was educated as a member of the aristocracy. At about the age of eighteen, he went to Athens to continue his education at Plato's Academy.

 Aristotle remained at the Academy for nearly twenty years, not leaving until after Plato's death in 347 BC. He then traveled with Xenocrates to the court of Hermias of Atarneus in Asia Minor. While in Asia, Aristotle traveled with Theophrastus to the island of Lesbos, where together they researched the botany and zoology of the island. Aristotle married Hermias' daughter (or niece) Pythias. She bore him a daughter, whom they named Pythias. Soon after Hermias' death, Aristotle was invited by Philip of Macedon to become tutor to Alexander the Great.

After spending several years tutoring the young Alexander, Aristotle returned to Athens. By 335 BC, he established his own school there, the Lyceum.

Aristotle directed courses at the Lyceum for the next twelve years. While in Athens, his wife Pythias died. Aristotle soon became involved with Herpyllis of Stagira, who bore him a son whom he named after his father, Nicomachus.

It is during this time in Athens that Aristotle is thought to have composed many of his works. Although Aristotle wrote dialogues, only fragments of these have survived. The works that have survived are in treatise form and, for the most part, were not meant for widespread publication.

These are generally thought to be lecture notes or texts used by his students. Among the most important are Physics, Metaphysics , Nicomachean Ethics, Politics, De Anima and Poetics. These works, although connected in many fundamental ways, differ significantly in both style and substance.