Aristotle's views on time have received sporadic attention over the years, but Ursula Coope's elegantly-written book is the first monograph available in English dedicated exclusively to the account that Aristotle develops in the final five chapters of Physics IV. Three topics form the thematic core of the book: time's relation to change, time's status as a kind of number, and the unity and diversity of times. I shall touch on each of these themes and indicate how I think Coope's interpretation fares. While I disagree with her reconstruction of the account on several central points, it exhibits a great deal of ingenuity and sophistication and deserves careful consideration.