Anti-aging guru Roizen and celebrated heart surgeon Oz combine their popular approaches to patient-centered care in this assessment of how much, or more to the point, how little, readers know about their bodies. After taking the quizzes in the book, readers may feel shocked by their ignorance of basic anatomy and the processes required to maintain physical and mental functioning. Each chapter focuses on a body part or system (heart, brain, digestive, reproductive, etc.) and discusses diseases associated with it, genetic and lifestyle influences on its aging process, and foods, supplements and habits that can prevent or reverse related illnesses. The book has an entertaining feel: friendly elves guide readers through illustrations of the body and cartoons feature alien creatures that enter the body and cause illness.