Begin with the book’s title and subtitle. The analogy between a map and a theory is a useful device. Fathers-in-law are always pointing out that any economic theory ignores this or that obvious fact about the real-world economy. But a map on the scale of one to one is precisely useless. A map on the scale of one to 500,000 is useful for most purposes, but you cannot expect it to show every bend in the road or every dirt track leading north. Greenspan does not seriously discuss the goals and the limitations of reasoning about the economy. - http://www.newrepublic.com/article/115956/alan-greenspans-map-and-territory-reviewed-robert-solow