Outlines of Scepticism, by the Greek philosopher Sextus Empiricus, is a work of major importance for the history of Greek philosophy. It is the fullest extant account of ancient skepticism, and it is also one of our most copious sources of information about the other Hellenistic philosophies. Its argumentative approach revolutionized the study of philosophy when Sextus’ works were rediscovered in the sixteenth century. This volume presents the accurate and readable translation that was first published in 1994, together with a substantial new historical and philosophical introduction by Jonathan Barnes.