 In the field of monetary theory, post-Keynesian economists were among the first to emphasise that money supply responds to the demand for bank credit, so that a central bank cannot control the quantity of money, but only manage the interest rate by managing the quantity of monetary reserves.This view has largely been incorporated into monetary policy, which now targets the interest rate as an instrument, rather than the quantity of money.In the field of finance, Hyman Minsky put forward a theory of financial crisis based on financial fragility, which has received renewed attention.