Stephen Everson presents a comprehensive new study of Aristotle's account of perception and related mental capacities. Recent debate about Aristotle's theory of mind has focused on this account, which is Aristotle's most sustained and detailed attempt to describe and explain the behaviour of living things. Everson places it in the context of Aristotle's natural science as a whole, showing how he applies the explanatory tools developed in other works to the study of perceptual cognition. Everson demonstrates that, contrary to the claims of many recent scholars, Aristotle is indeed concerned to explain perceptual activity as the activity of a living body, in terms of material changes in the organs which possess the various perceptual capacities. By emphasizing the unified nature of the perceptual system, Everson is able to explain how Aristotle accounts for our ability to perceive not only such things as colours and sounds but material objects in our environment. This rich and broad-ranging book will be essential reading not only for students of Aristotle's theory of mind but for all those concerned to understand the explanatory principles of his natural science. 'No part of Aristotle's psychological theory has been of greater interest to scholars over the past few years than his account of perception. . . . this excellent book . . . will appeal to Aristotelian scholars and philosophers of mind alike . . . Everson manifests a thorough understanding of much of the literature on Aristotle's psychological theory and displays a talent for offering sophisticated arguments that are informed by the conceptual possibilities demarcated in both ancient and modern philosophy . . . Everson has presented a rich and insightful critique of a thesis which has had significant impact upon contemporary discussions of Aristotle's psychological theory. Further, in offering ths critique, he has avoided many of the snares and entanglements to which others have fallen prey.' John E. Sisko, Oxford Studies in Ancient Philosophy