On the whole, the monetarism for which Friedman first became famous seems clever, brilliantly argued, but shallow ― and perhaps even a bit disingenuo… - Paul Krugman

In the last few years it has become apparent that during the 1940s and 1950s, a core of ideas emerged regarding external economies, strategic complementarity, and that remains intellectually valid and may continue to have practical applications. This set of ideas which I will refer to as "high " — anticipated in a number of ways the cutting edge of modern trade and growth theory. But these ideas have had to be rediscovered. Between 1960 and 1980 high development theory was virtually buried, essentially because the founders of development economics failed to make their points with sufficient analytical clarity to communicate their essence to other economists, and perhaps even to each other. Only recently have changes in economics made it possible to reconsider what the development theorists said, and to regain the valuable ideas that have been lost.

So the story of the baby-sitting co-op is not a mere amusement. If people would only take it seriously—if they could only understand that when great economic issues are at stake, whimsical parables are not a waste of time but the key to enlightenment—it is a story that could save the world.

There are many economic puzzles, but there are only two really great mysteries.
One of these mysteries is why economic growth takes places at different rates over time and across countries. Nobody really knows why the U.S. economy could generate 3 percent annual productivity growth before 1973 but only 1 percent afterward, nobody really knows why Japan surged from defeat to global economic power after World War II, while Britain slid slowly into third-rate status. At any given time there are always policy entrepreneurs willing to claim that they have all the answers, but we'll come to that story in later chapters.
The other mystery is the reason why there is a business cycle ― the irregular rhythm of recessions and recoveries that prevents economic growth from being a smooth trend. It was in challenging the orthodox, Keynesian view of business cycles that conservatives first forced a major rethinking of economics.