My paper examines how Lange integrated the Walrasian and the Keynesian ingredients in his research. I argue that his works proposed two kinds of macroeconomics. The first kind was IS-LM, but IS-LM interpreted as an aggregate version of Walras' general equilibrium model (Lange, 1938). The second kind was developed in Lange's 1944 book. There, macroeconomic became a subfield of stability analysis. The paper highlights Hicks' (1939) decisive influence on Lange. It shows that Value and Capital revealed to Lange how he could use the Walrasian framework to unveil the inherent instability of the capitalist system. This part of the paper help us assess Lange's achievements and his influence on the generation of Modigliani, Solow and Patinkin.
