We have a certain heroic expectation of how medicine works. Following the Second World War, penicillin and then a raft of other antibiotics cured the scourge of bacterial diseases that it had been thought only God could touch. New vaccines routed polio, diphtheria, rubella, and measles. Surgeons opened the heart, transplanted organs, and removed once inoperable tumors. Heart attacks could be stopped; cancers could be cured. A single generation experienced a transformation in the treatment of human illness as no generation had before. It was like discovering that water could put out fire. We built our health-care system, accordingly, to deploy firefighters. Doctors became saviors. ... But the model wasn’t quite right. If an illness is a fire, many of them require months or years to extinguish, or can be reduced only to a low-level smolder. The treatments may have side effects and complications that require yet more attention. Chronic illness has become commonplace, and we have been poorly prepared to deal with it. Much of what ails us requires a more patient kind of skill. ... Observing the care, I began to grasp how the commitment to seeing people over time leads primary-care clinicians to take an approach to problem-solving that is very different from that of doctors, like me, who provide mainly episodic care.