Between Labor and Capital

What are the functions and class alliances of those between labor and capital: technicians, managers, administrators, professionals, service workers, teachers, scientists? The lead piece by Barbara and John Ehrenreich sets forth the thesis that there is a third class in advanced capitalist society. "The Professional Managerial Class," whose "objective class interest lies in the overthrow of the capitalist class, but not in the triumph of the working class." In the second part, authors representative of the major left positions directly debate the revolutionary potential of those people whose function is to reproduce capitalist social relations. Do those who work between labor and capital constitute a third class, or with different sectors tend to ally with either the working class or the capitalist class, or is a whole new conception of the dynamics of social change necessary?