The pressure for falling prices is gathering momentum. The producer price index plunged by a record 2.8% in October. That follows on an 0.4% drop in September. Still, the slight rise in the core producer price index--a number that excludes fuel and food--was up a fraction.

High on the list of things the monetary authorities need to worry about is deflation, or an overall fall in the price level. A few years ago, I wrote a book Deflation: What Happens When Prices Fall?

It's a timely read.