Imagine cancer, 2040. A 45-year-old woman who has never smoked develops lung cancer, which today kills more people than any other kind. (By then, of course, cigarettes will have gone the way of the buggy whip, and lung cancer rates will be cut in half.) She undergoes outpatient surgery, and her doctors quickly scrutinize the tumor’s genes and feed the data, along with other information from her electronic medical record, into a desktop computer that crunches out a treatment plan all but certain to work. At subsequent checkups, her blood is tested for the earliest hint of a tumor recurrence-though were such news to come, it would bring no doom and gloom. Her doctor would simply analyze a few of the cells that even the tiniest tumors shed and prescribe a suitable next round of therapy. Throughout, her busy life is barely interrupted, and her hair stays wonderfully intact.