Cosmas and Damian are legendary twin brothers from the early days of Christianity who are venerated for their special healing powers. They are also canonised Roman Catholic saints who are considered to be the patron saints of transplant patients. The twin healers were martyred for their faith in 300 AD on land that today lies within the borders of Syria. Jacalyn Duffin, whose area of specialty is the history of medicine, has written an interesting book about her experiences tracing the saints' intercessory roles in today's world. The book is an autobiographical memoir, but is richly threaded through with history, psychology, travelogue and social science. This blend of genres, then, is a somewhat unusual offering from Oxford University Press.