With this lecture, we begin to treat the four-dialogue sequence devoted to Socrates’s trial, conviction, and execution. The Euthyphro is set on the steps of the courthouse that Socrates is about to enter to attend a preliminary hearing prior to his trial. The question treated in the dialogue is of obvious importance to that trial, for he and Euthyphro discuss the question, “What is piety?” We will begin with an account of the dialogue’s most prominent features, especially the surprising circumstances surrounding it. Second, we will take up in turn each of the main arguments concerning piety. Third and finally, we’ll consider a summary of the dialogue showing the general approach Socrates took to the challenge that orthodox piety poses to the philosophic life, the life of reason.