CPhilosophy Substance and Essence in Aristotle is a close study of Aristotle's most profound and perplexing-treatise: Books VII-IX of the Metaphysics. Charlotte Witt extracts from this text a coherent and provocative view about sensible substance by focusing on Aristotle's account of form or essence. After exploring the context in which Aristotle's discussion of sensible substance takes place, Witt turns to his analysis of essence. Arguing against the received interpretation, according to which essences are classificatory, she maintains that a substance's essence is what causes it to exist. In addition, Witt challenges the orthodox view that Aristotelian essences are species-essences, defending instead the controversial position that they are individual essences. Finally, Witt compares Aristote- lian essentialism to contemporary essentialist theories, focusing in particular on Saul Kripke's work.