In this lecture divided into 10 chapters, Dr. Groopman and Dr. Hartzband present practices that were little outside the range of what part is conventional medicine and the challenge an interest off building science around this practice. In front of several controversies both in the medical literature published through guidelines and available in the media, on the prevention and treatment of various diseases, the question is: Why do the professionals disagree? Why is not there a clear answer? How can patients decide on the best course of action to deal with so many controversies? They finalize by pointing out that in order to find the best decision for a treatment in the face of so many controversies, in addition to consider the scientific studies with evidence, good medical-patient communication should be considered and that each individual seeks to find the best treatment for him as an individual.