Empirical research into entrepreneurs has indicated that they do not comprise a homogeneous category, but include the self-employed, small employers, owner-controllers and owner-directors (Scase and Goffe, 1982). Sociological analysis of the self-employed – small proprietors, artisans and tradespeople – has occupied a problematic place in the study of the changing class structure of capitalist societies in terms of their position between large-scale capital and the working class (see PETTY BOURGEOISIE). Interest in the self-employed has been renewed recently with the proliferation of small businesses and research into the INFORMAL ECONOMY. The class position of owner-controllers and owner-directors has figured prominently in the analysis of the separation of ownership from control, and of the RULING CLASS in advanced capitalist societies. See also MANAGERIAL REVOLUTION, POSTCAPITALISM AND POSTCAPITALIST SOCIETY.