The Sophist is a dialogue by Plato (b. c. 427–d. c. 347 bce) that modern scholarship unanimously places in his later period. This placement connects it with the other later dialogues; namely, the Statesman, Timaeus, Critias, Philebus, and Laws. Also, it is closely related to the preceding dialogues of the transitional period; namely, the Parmenides and Theaetetus. The classification of “later dialogues,” originally suggested by Lewis Campbell in 1867, is now a common view of the Platonic chronology. Scholars normally assume that Plato wrote it after the second voyage to Sicily (c. 366–365 bce) in his early sixties. The official theme of the Sophist is to examine and define the Sophist, which had been a major concern for Plato since the earlier dialogues (e.g., the Apology of Socrates, Gorgias, Protagoras). The method of division (diairesis), employed for definition, is originally suggested in the Phaedrus and is used also in the Statesman and Philebus. But the inquiry into the Sophist faces several difficulties of philosophical importance concerning falsehood, image, not-being, and being. After solving these difficulties, it finally defines the Sophist as “imitator of the wise.” The dialogue covers a wide range of philosophical subjects and is famous for substantial discussions on ontology, epistemology, logic, and the philosophy of language. Ontological questions such as the following are asked: Can we speak or think of not-being? What is being? The examination provides a basis for logic and epistemology in the following questions: How is there a falsehood? What are a statement (logos), a judgment, and an appearance (phantasia)? Then, modern scholars ask what negation is, and how one can distinguish between different uses of the verb “to be.” Finally, the examination of the true nature of the Sophist raises issues of education, ethics, politics, rhetoric, aesthetics, and cosmology. The dialogue was probably read and discussed in Plato’s Academy and therefore greatly influenced later philosophers. Aristotle took over many achievements of the inquiry, such as definitions of “statement” and “truth/falsehood,” and critically used the method of division. Since the mid-20th century, the analytical approach has shed new light on the logical aspects of the dialogue (in particular, falsehood, negation, and the verb “to be”), so the context and development of scholarly arguments have to be taken into consideration, while many earlier studies keep their interpretative values. More-recent studies show a wider variety of approaches to the dialogue (different from the analytic tradition).