Aristotle's "Categories" is a short but influential work in philosophy that explores the nature of language and the relationship between words and concepts. In this treatise, Aristotle sets out to identify the various types of concepts and categories that underlie human thought and communication. The work is structured around ten categories, or groups of concepts, that Aristotle sees as fundamental to human understanding. These categories include substance, quantity, quality, relation, place, time, position, state, action, and affection. Aristotle argues that all objects and ideas can be understood in terms of these categories, and that they form the basic building blocks of human thought and language.