Prevention of disease and injury, including early identification of risks and disease and optimal control of potentially debilitating or fatal complications of chronic conditions, is the area of clinical medicine that holds the greatest promise for improving human health. Each year a long list of major, but potentially preventable health problems exacts a terrible human and financial toll. These problems urgently need our attention, especially as major advances in curative medicine become more complex and costly. Prevention of disease and injury may well be the central health issue of our...