Raymond Aron (1905–1983) was a French sociologist, philosopher, political actor, and commentator. Before World War II, he lectured in several French universities (Le Havre, Bordeaux, Toulouse). In 1938, he defended his doctoral thesis Introduction to the Philosophy of History, which was published as a book and widely reviewed in Europe and the United States. After graduating, he spent the years from 1930 to 1933 in Germany and observed the rise of National Socialism. In 1935, he published German Sociology in which he made the distinction between “systematic” and “historical” sociology. Systematic sociology was concerned with “fundamental social relations, types of social groups [and] the static structure of society,” while historical sociology focused on the “laws, or at least the theory, of the development of the bourgeois society” (Aron, 1957 [1935]: 2).