Models of Inflation

Inflation was too high in the 1970s and early 1980s because mainstream economists had a poor understanding of when inflation is beneficial and when it is harmful and of how to control it.  Today inflation is too low because mainstream economists have a poor understanding of the costs and benefits of inflation and how to control it.  In some ways, we are in the mirror image of the problems of the 1970s. 
Lowering inflation is simple.  Just restrict the money supply and communicate expectations clearly.  Raising inflation is also simple.  Just expand the money supply and communicate expectations clearly.  The important think in both cases is for the central bank to clearly communicate that it will keep doing whatever it takes to bring inflation to the approximate level that it wants.  Today it seems amazing that economists did not understand this in the 1970s and someday it will seem amazing that many prominent economists do not understand this today.