Karl Marx’s most vital contribution to modern class analysis was to document the ways in which capitalist owners continually extract unpaid labor from hired workers in the production process as a primary source of their profits.

After his death, many analysts overlooked his focus on this “hidden abode” of production in the capitalist labor process, focusing instead on the inequitable distribution of commodities. Later Marxist intellectuals and others insightfully analyzed other devastating general effects of capitalist development. But the labor process focus was resurrected in the wake of the student-worker protests of the 1960s, most notably by Harry Braverman’s Labor and Monopoly Capital: The Degradation of Work in the Twentieth Century (1974). An array of studies followed to identify the class structure of advanced capitalist societies based on paid workplace relations between owners and hired employees.

Marx’s original interest in identifying conditions in which hired workers would develop a class consciousness opposing capitalism faced a similar path: many assertions of the necessity for class consciousness but little empirical investigation of its existence — until the protests of the ’60s sparked an array of studies, such as Michael Mann’s Consciousness and Action Among the Western Working Class (1973). These distinctive studies of class structure and class consciousness occurred as organized labor reached historic membership highs and labor’s share threatened normal profit margins in many capitalist economies. These developments led to the onslaught of capital’s neoliberal counterattack.