This is an English translation of four of Plato's dialogue (Protagoras, Euthydemus, Hippias Major, and Cratylus) that explores the topic of sophistry and philosophy, a key concept at the source of Western thought. Includes notes and an introductory essay. 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.