 The history of the study of fallacies begins with Aristotle’s work, On Sophistical Refutations. It is among his earlier writings and the work appears to be a continuation of the Topics, his treatise on dialectical argumentation. Although his most extensive and theoretically detailed discussion of fallacies is in the Sophistical Refutations, Aristotle also discusses fallacies in the Prior Analytics and On Rhetoric. Here we will concentrate on summarizing the account given in the Sophistical Refutations. In that work, four things are worth noting: (a) the different conceptions of fallacy; (b) the basic concepts used to explain fallacies; (c) Aristotle’s explanation of why fallacies can be deceptive; and (d) his enumeration and classification of fallacies.