Pyrrhonian skepticism is defined by its commitment to inquiry. The Greek work skepsis means inquiry—not doubt, or whatever else later forms of skepticism took to be at the core of skeptical philosophy. The book proposes that Sextus Empiricus’s legacy in the history of epistemology is that he developed an epistemology of inquiry. The volume’s authors investigate epistemology after Sextus, both ways in which he has influenced the history of philosophy and ways in which he and the Pyrrhonian tradition he represents ought to contribute to contemporary debates. As a whole, the book aims to (re)instate Sextus as an important philosopher in these discussions in much the same way that Aristotle has been brought into discussions in contemporary ethics, action theory, and metaphysics. Sextus provides a fresh take on contemporary debates because he approaches issues of perception, disagreement, induction, and ignorance from the perspective of inquiry. The volume’s contributions address four core themes of Sextus’s skepticism: (1) appearances and perception, (2) the structure of justification and proof, (3) belief and ignorance, and (4) ethics and action. These themes are explored in some historical authors whose work relates to Sextus, including Peripatetic logicians, Locke, Hume, Nietzsche, and German idealists; and they are explored as they figure in today’s epistemology, philosophy of mind, philosophy of language, and ethics.