The subject of the course is the theoretical evolution of monetary theories during the XX century, starting from Keynes’ contributions, General Theory and his proposals for the reconstruction of international monetary system (bancor) in the Forties. From this premise the monetary upswing led by Milton Friedman will be explained. A special attention will be paid to Minsky’s analysis of financial instability and to Mandelbrot’s criticism of the mainstream financial theory and its postulates.