"A must-read for any student and scholar interested in Aristotle's view of pneuma. In short, this book is a masterpiece, distilling many years of research of a great Aristotelian scholar." — Review of Metaphysics"[Bos's] knowledge of the Aristotelian corpus is impressive … the book deserves to be taken seriously as a valuable contribution to Aristotelian scholarship." — Philosophia Reformata"Bos offers a fresh, interesting, and important perspective. His interpretation will be very controversial, but if he is right, the standard Anglo-American interpretation of Aristotle will have to change radically." — Malcolm Wilson, author of Structure and Method in Aristotle's Meteorologica: A More Disorderly Nature