Clinical epidemiology. what, who, and whither.

Clinical epidemiology, the what, was introduced by John Paul in 1938, as a new basic science for preventive medicine. Its definition subsequently took on a more bedside tone, but continues to be adapted to the needs of its practitioners. Clinical epidemiology, the who, centers on Alvan Feinstein and the way that he led the field and nurtured so many of its practitioners. Clinical epidemiology, the whither, describes its more recent development and its impact on five evolutions and revolutions: in evidence generation, its rapid critical appraisal, its efficient storage and retrieval, evidence-based medicine, and evidence synthesis.