An intelligent, original, and readable book. It not only advances a new interpretation of Aristotle's theory of substance but also explores new connections between Aristotle's theory and problems concerning theory of prediction that arise out of Plato's theory and out of Aristotle's own early thought on the subject. -Mohan Matthen, University of British Columbia Scaltsas has written an extended and powerful treatment of some of the deepest and most puzzling features of Aristotelian metaphysics, producing an interpretation that covers a wide range not only of Aristotelian material but also of Platonic material. He offers detailed critiques of the views of various modern commentators as well as of philosophers. Scaltsas has made an important and original contribution to our interpretation of Metaphysics. -Philosophical Quarterly