Consideration of the body and soul as two aspects of a single unique substance. In their relationship, these two are understood as matter and form. The soul as the entelechy of the individual. Aristotle, son of the physician Nicomachus, was born in Stagira in 384 BC. Information about the early years of his life is scarce. At the age of seventeen, he went to Athens to study at the Platonic Academy. He stayed there for twenty years, from 367 to 348 BC, when Plato died. Then Aristotle left for Assos in the Troad, and after a three-year stay there, he went to Lesbos and then to Macedonia, where he undertook the education of the royal child Alexander. When his student ascended the throne, Aristotle settled in Athens and founded his school, the Lyceum. After the death of Alexander (323 BC), the philosopher's stay in Athens became difficult. He was forced to take refuge in Chalcis, his mother's homeland, where he died in 322. A universal spirit, Aristotle created a vast and valuable body of philosophical and scientific work. Epistemology, logic, theology, physics, biology, psychology, ethics, political philosophy, and aesthetics are the main fields of knowledge he explored and studied. The Alexandrian Hermippus estimated Aristotle's works at 400. Lists that include 143 titles of his works have survived to us. Diogenes Laertius estimated the number of lines in Aristotle's writings at 440,000. The impact of his work on the shaping of global thought was, for centuries, and remains, strong. [Excerpt from publisher or edition presentation text]