[Clinical research in service of clinical medicine: Contexts, practice, methodolody, and theory of Paul Marini's "clinical proof" - part 1].

This is the first contribution to a quadripartite series on Paul Martini, internist and early clinical epidemiologist (1889-1964), and his clinical proof ("klinischer Beweis"). Following a historical introduction and the presentation of our programme, the text deals with Martini as a person and his socio-cultural background between the end of the Great War and the 1960s. It throws light on his original, innovative and risky research programme, and outlines various factors which led Martini to his central life issue: the therapeutic-clinical proof based on controlled investigations.