Diagnosis, once the cornerstone of medicine, is fast becoming a lost art, with grave consequences, argues Dr. Leana Wen. She talks about the doctor-patient relationship, uses real-life stories of diagnoses-gone-bad, and explains how active patient participation can prevent these mistakes. Her book When Doctors Don’t Listen: How to Avoid Misdiagnosis and Unnecessary Tests offers follow-up questions patients can incorporate into every doctor’s visit to get better care and to avoid counterproductive and potentially harmful tests.