Erwin H. Ackerknecht was an influential member of that small group of largely émigré historians of medicine who professionalized their field in the United States. Ackerknecht was influenced by both contemporary social science and an implicitly political vision of social medicine. It was a vision reinforced by his work in social anthropology in Paris in the 1930s, and it is a tradition that has its own intellectual pedigree, one that can be traced back to the era of Rudolf Virchow. It was no accident that Ackerknecht wrote on the social and ecological dimensions of disease, and that he was a vigorous advocate of a powerfully felt but, in retrospect, inconsistent relativism. His emphases on everyday medical practice and on siting ideas in their social and institutional context seem prescient, a forerunner of contemporary trends in social and cultural history.