Erwin Heinz Ackerknecht (1 June 1906 – 18 November 1988) was an active and influential Trotskyist in the 1930s who had to flee Germany in 1933 after Hitler’s rise to power. It was in the United States, the country that granted him citizenship, that Ackerknecht became an influential historian of medicine. He wrote groundbreaking works on the social and ecological dimensions of disease and was a forerunner of contemporary trends in social and cultural history. He became the first Chair in the history of medicine at the University of Wisconsin; the second such position in the United States.[1]