"Categories" is a philosophical work written by Aristotle, which is widely considered to be one of the most influential works in the history of Western philosophy. The work explores the nature of reality and how it can be classified into different categories. Aristotle begins by examining the concept of substance, which he defines as the fundamental nature of a thing. He then goes on to consider other categories such as quality, quantity, relation, place, time, position, state, and action. These categories help to organize our understanding of the world and provide a framework for understanding the various phenomena that we encounter. Read in English, unabridged.