we remain committed to the view that it is a mistake simply to throw aggregate demand and aggregate supply curves at students in the first few chapters of a principles book. to understand the AS and AD cures students need to know about the functioning of both the goods market and the money market. the logic behind the simple demand curve is wrong when it is applied to the relationship between aggregate demand and the price level. Similarly the logic behind the simple supply curve is wrong when it is applied to the relationship between aggregate supply and the price level.