This document provides an introduction and summary of Plato's dialogue "Protagoras". The introduction describes the setting of the dialogue as taking place at the house of Callias, with Socrates, Protagoras, Hippias, Prodicus, Alcibiades and Critias in attendance. Socrates questions Protagoras about what he can teach and whether virtue can be taught. Protagoras provides an allegory in response. Socrates then questions whether virtues are one or many, trapping Protagoras in contradictions through dialectic questioning. The dialogue continues with debates over the interpretation of a poem by Simonides.