A re-examination of the question why, in the revival of interest, in the first century BC in Aristotle’s esoteric works, as opposed to his doctrines, the work Categories played so large a part. The answers suggested are that the work aroused interest just because it did not easily fit into the standard Hellenistic divisions of philosophy and their usual agendas, and that, more than Aristotle’s other works with the possible exception of the Metaphysics , it revealed aspects of Aristotle’s thought that had become unfamiliar during the Hellenistic period.