When Bechara Choucair was a young doctor, he learned an important lesson: treating a patient for hypothermia does little good if she has to spend the next night out in the freezing cold. As health commissioner of Chicago, he was determined to address the societal causes of disease and focus the city's resources on its most vulnerable populations. That targeted approach has led to dramatic successes, such as lowering rates of smoking, teen pregnancy, breast cancer mortalities, and other serious ills. In Precision Community Health, Choucair shows how those successes can be replicated and expanded around the world. The key is to use advanced technologies to identify which populations are most at risk for specific health threats and avert crises before they begin. Big data makes precision community health possible. But in our increasingly complex world, we also need new strategies for developing effective coalitions, media campaigns, and policies. This book showcases four innovations that move public health departments away from simply dispensing medical care and toward supporting communities to achieve true well-being. The approach Choucair pioneered in Chicago requires broadening our thinking about what constitutes public health. It is not simply about access to a doctor, but access to decent housing, jobs, parks, food, and social support. It also means acknowledging that a one-size-fits-all strategy may exacerbate inequities. By focusing on those most in need, we create an agenda that is simultaneously more impactful and more achievable. The result is a wholesale change in the way public health is practiced and in the well-being of all our communities.