This article analyses knowledge production about itinerant groups such as Nightmen, Roma and Travellers in Den-mark between 1800 and 1950. It puts forward the thesis of a Danish Sonderweg in this regard, not only compared with Germany, but also the Scandinavian neighbours. This Sonderweg was characterized by an underdeveloped interest of science and state authorities for respective groups and culminated into a rejection of forced eugenic measures. The analysis is based on key texts from three periods: a national romantic one from approximately 1800 onwards, one shaped by the Danish Gypsy LoristJohan Miskow at the beginning of the 20th century, and one eugenic from 1938. Special interest is given to continuities and fractions in narratives of purity vs. mixture.?