This is an English translation of Plato's dialogue concerning the nature of knowledge. In this dialogue, Socrates and Theaetetus discuss three definitions of knowledge: knowledge as nothing but perception, as true judgment and as true judgment with an account.

Focus Philosophical Library translations are close to and are non-interpretative of the original text, with the notes and a glossary intending to provide the reader with some sense of the terms and the concepts as they were understood by Plato's immediate audience.