On p. 33, he writes,
it’s far easier to understand inflation and deflation if we think in terms of explaining changes in the value of money than if we try to imagine the factors that would be changing the prices of each and every good, service, and asset in the economy.
During much of the Great Inflation [1966-1981, in his telling], people did try to explain the problem by searching for factors that were pushing up specific wages and prices. Indeed, in a sense the Great Inflation was caused by this misconception.
As I see it, we are seeing the same misconception this year. But on his blog, Sumner seems to disagree. He is willing to buy into the theory that we are facing transitory supply shocks in a few sectors. I think the main reason he goes with this story is that trust in the forecasting ability of financial markets is part of his worldview. But financial markets got it wrong during the Great Inflation, also.
I have just started the book. I am sure I will have more to say about it at a later date.