This book explores the nature and significance of Pyrrhonism, the most prominent and influential form of skepticism in Western philosophy. Not only did Pyrrhonism play an important part in the philosophical scene of the Hellenistic and Imperial age, but it also had a tremendous impact on Renaissance and modern philosophy and continues to be a topic of lively discussion among both scholars of ancient philosophy and epistemologists. The focus and inspiration of the book is the brand of Pyrrhonism expounded in the extant works of Sextus Empiricus. Its aim is twofold: to offer a critical interpretation of some of the central aspects of Sextus¿s skeptical outlook