"Sophist" is one of Plato's dialogues, believed to have been written in the middle period of his philosophical career, around 380 BCE. In this dialogue, Plato explores the nature of sophistry, the art of persuasion, and the distinction between true knowledge and mere opinion.

The dialogue takes place between Socrates and several interlocutors, including a Visitor from Elea and a young philosopher named Theaetetus. The conversation revolves around the question of whether or not it is possible to define what a sophist is, and if so, how to distinguish between sophists and philosophers.

The central theme of "Sophist" is the examination of the nature of reality and the challenge of distinguishing between appearance and reality. The characters engage in a dialectical inquiry, attempting to define the essence of sophistry and to differentiate it from genuine philosophical inquiry.

Plato uses the dialogue form to present various arguments and counterarguments, illustrating the Socratic method of inquiry and philosophical investigation. Through logical analysis and rigorous questioning, Socrates and his interlocutors explore the complexities of language, knowledge, and ontology.

Overall, "Sophist" is a profound philosophical work that delves into fundamental questions about truth, knowledge, and the nature of reality. It is a challenging and thought-provoking dialogue that continues to stimulate scholarly debate and philosophical inquiry to this day.