In his Essays in the Theory of Business Cycle published in Polish in1933, Kalecki clearly stated the principle of effective demand inmathematical form. By 1935 he outlined his theory of employment,demolished the then-orthodox remedy for a depression-that is, wagecutting-and pinpointed the importance of investment for economicdynamics. Thus, although his training had been in Marxist economics, hesucceeded in anticipating the Keynesian system, and, as Joan Robinsonhas pointed out, his claim to priority of publication is indisputablealthough he never mentioned this fact.