From New York Times bestselling author and world-renowned doctor and geneticist Francis Collins, a book that will forever change how you think about your body, your health, and the future of medicine. A scientific and medical revolution has crept up on us, based on study after study, from hundreds of laboratories around the world. It is no longer just a theoretical shift: every one of us will be touched by it, and many of us already have been. The meaning of disease, our understanding of the human body, and crucial decisions about what we all need to know and what choices we make about our health are at stake. Welcome to the new world of personalized medicine. Twenty-one million Americans are affected by 6,000 so-called rare and orphan diseases, many of which are primarily attributable to misspelled genes. And virtually all diseases have a significant hereditary component. There have been many stories in the media about women who are testing to see if they have a mutation that leads to