This volume emerged from the Wiles Lectures delivered at Queen's University, Belfast, in 2006, and the four chapters of the work retain their original character. The tone is light and breezy throughout. Complex problems are rendered accessible, such that the book might work well in advanced undergraduate courses dealing with medieval science, intellectual culture, or magic. The topic Bartlett tackles is obviously enormous, and in the scope of four short lectures, he can only begin to address the many profound issues that arise from serious consideration of what the Middle Ages meant by "natural" and "supernatural." Experts will not find much new ground broken. Neither is the work a systematic overview, focusing more often on well-chosen examples rather than presenting a coherent survey, but it succeeds admirably in providing clear illustrations of major trends.