 However, even if the labour theory of value is considered discredited, there are elements of his theory that remain of worth. The Cambridge economist Joan Robinson, in An Essay on Marxian Economics (1942), picked out two aspects of particular note. First, Marx’s refusal to accept that capitalism involves a harmony of interests between worker and capitalist, replacing this with a class-based analysis of the worker’s struggle for better wages and conditions of work, versus the capitalist’s drive for ever greater profits. Second, Marx’s denial that there is any long-run tendency to equilibrium in the market, and his descriptions of mechanisms which underlie the trade-cycle of boom and bust. Both provide a salutary corrective to aspects of orthodox economic theory.