Theodor Geiger grew up in Germany and emigrated to Denmark in 1933, threatened by the Nazi regime. He worked at the University of Copenhagen 1933-38 and was the first Professor of Sociology at the University of Aarhus 1938-52. He spent 3 years in exile in Sweden. Geiger is an important figure in German and Scandinavian sociology and also known in English-speaking countries. He was a prolific teacher and writer. Throughout his life as a sociologist Geiger combined theoretical with empirical interest. If he rejected all speculation without a factual basis, he showed an equally strong disdain for empiricism without a theoretical foundation (Mayntz 1969). His works cover a broad spectrum of subjects, still of professional interest, such as: the foundation and fundamental concepts of sociology, the education of working-class people, industrial organization, class structure, stratification and mobility, social origin and functions of the intelligentsia, the sociology of law, critics of ideology and the nature of modern mass-society and democracy.