Cervero explores the mechanisms and the meaning of pain. You touch something hot and your brain triggers a reflex action that causes you to withdraw your hand. That kind of pain is actually good for us; it acts as an alarm that warns us of danger and keeps us away from harm. There is another kind of pain that is more like a curse: chronic pain that is not related to injury. Cervero describes current research into the mysteries of chronic pain and efforts to develop more effective treatments.