David Charles presents a study of Aristotle's views on meaning, essence, necessity, and related topics. These interconnected views are central to Aristotle's metaphysics, philosophy of language, and philosophy of science. They are also highly relevant to current philosophical debates. Charles aims, on the basis of a careful reading of Aristotle's texts and many subsequent works, to reach a clear understanding of his claims and arguments, and to assess their truth and their importance to philosophy ancient and modern.