Summary: In about 1000 words the entry identifies the concept as a key one for the analysis of the socio-economic and political reality of states since the late 18th century, lays out the Marxian conception and his class theory, and ends with a discussion of Max Weber's use of the concept. With the industrial revolution two new social groups emerged which increasingly determined the social structure and political conflicts in industrialized capitalist states: free entrepreneurs and free workers. While class has been used to categorize these two groups before Marx, it was him as the entry argues who developed an encompassing class theory. History in Marx view is the history of class conflict, while the industrial revolution lead to the separation of the society into two antagonistic classes: bourgeoisie and proletariat. Membership in either one of them is dependent on the possession of means of production. In the long run Marx anticipated the development of a class-less society with the emancipation of the proletariat. The entry summarizes post-Marxian contributions to a class theory, and asks what the value of this approach is for the understanding of contemporary conflicts in Western capitalist countries. While no definite answer is given the entry argues that the transformation of production methods and the differentiation of the work force questions the analytical power of a class oriented approach in a post-industrial society. Therefore Max Weber's approach is viewed in more positive light, who more extensively differentiated between classes within the two general ones owner classes' and employees classes.' The entry ends with the suggestion that in addition a group of classes should be considered for the analysis of contemporary politics whose members social situation is at least partially dependent on state transfers.