This book is a re-thinking of Aristotle's metaphysical theory of material substances. The view of the author is that the 'substances' are the living things, the organisms: chiefly, the animals. There are three main parts to the book: Part I, a treatment of the concepts of substance and nonsubstance in Aristotle's Categories; Part III, which discusses some important features of biological objects as Aristotelian substances, as analysed in Aristotle's biological treatises and the de Anima; and Part V, which attempts to relate the conception of substance as interpreted so far to that of the...