Christian Pfeiffer explores an important, but neglected topic in Aristotle's theoretical philosophy: the theory of bodies. For Aristotle, physical science deals with perceptible substances, such as humans, dogs, or the four elements. Substances are bodies, that is to say, they are extended, their parts are continuous with each other and they have boundaries, which demarcate them from their surroundings. The book is the first comprehensive and rigorous account of the features substances have in virtue of being bodies. It is not only of scholarly interest because our concept of a material object is intimately tied to its spatial or topological properties. That being said, the book is unique in explicitly arguing for the need of such an account within Aristotle's natural philosophy. Many claims Aristotle makes about the infinite, motion, or place presuppose a general theory of body.