I wish to add my heart-felt approval to many others, regarding the awarding of the Nobel Prize in Economics to Paul Krugman. For those readers of the New York Times who can only think of him as a columnist, let me assure you that long before he ever wrote a newspaper opinion piece, Krugman had become the leading international economist of my generation. I leave it to others to explain the trade theory research that earned the ultimate accolade. I will only say that (together with Elhanan Helpman) Krugman took traditional trade theory – which ever since David Ricardo had assumed perfect competition, constant returns to scale, and unchanging technology – and made it more realistic by assuming imperfect competition, increasing returns to scale, and endogenous technology.