Commentary: ways of asking and ways of living: reflections on the 50th anniversary of Morris' ever-useful Uses of Epidemiology.

To be of use. To Jeremy Morris (b. 1910), writing a half-century ago in his now classic text, Uses of Epidemiology, the promise—and responsibility—of epidemiology was clear: to generate scientific knowledge about the ‘presence, nature and distribution of health and disease among the population’ (p. 96), ultimately in order to ‘abolish the clinical picture’(p. 98). Committed to improving the ‘health of the community’ (p. 96),Morris argued that ‘one of the most urgent social needs of the day’ that epidemiology could address was ‘identifying harmful ways of living’ and ‘rules of healthy living’ (p. 98). Uniquely equipping epidemiology to carry out this task was, in his view, its population and historical perspective and its dual engagement with studying ‘human biology’ and ‘the social aspects of health and disease’ (p. 97). Viewing epidemiology as a necessary complement to what he deemed equally vital clinical and laboratory research (p. 99), Morris affirmed that the discipline’s distinct uses ‘all stem from the fact that in epidemiology the group is studied and not merely particular individuals or cases in the group’ (p. 97). How might epidemiologists enhance their capacity to do useful research? Morris’ answer: by use of better methods. Only the sort of methods Morris had in mind were not the kinds of technical methods emphasized by the ‘modern epidemiology’ of recent years, as necessary as he knew them to be. Rather, Morris’ objective was to articulate a methodical approach for epidemiological thinking: