Any interesting model of must exhibit a tension between two kinds of forces: "centripetal" forces that tend to pull economic activity into agglomerat… - Paul Krugman

in goods and services has expanded steadily over the past six decades thanks to declines in shipping and communication costs, globally negotiated reductions in government s, the widespread outsourcing of production activities, and a greater awareness of foreign cultures and products. New and better communications technologies, notably the Internet, have revolutionized the way people in all countries obtain and exchange information.

If Keynes was Luther, Friedman was Ignatius of Loyola, founder of the Jesuits. And like the Jesuits, Friedman’s followers have acted as a sort of disciplined army of the faithful, spearheading a broad, but incomplete, rollback of Keynesian heresy. By the century’s end, classical economics had regained much though by no means all of its former dominion, and Friedman deserves much of the credit.

Whether the influence of increasing returns on trade and geography is rising or falling, one thing is clear: much was learned from the intellectual revolution that brought increasing returns into the heart of how we think about the world economy. It wasn't just that economists could make sense of previously puzzling data, we found ourselves able to see things that had previously been in an intellectual blind spot. Many people contributed to this process of enlightenment; I'm proud to have been a part of the journey.