This article is based on Kalecki's * 1934 study entitled 'Three Systems'. It aims to show that before the General Theory Kalecki developed a mathematical model capable of expressing both the main conclusions of the neoclassical theory - Kalecki's Systems I and II - and the persistence of...

Oskar Lange's 1938 article "The Rate of Interest and the Optimum Propensity to Consume" is usually associated with the original IS-LM approach of the late 1930s. However, Lange's article was not only an attempt to illuminate Keynes's main innovations but the first part of a wide project that...