Paul Krugman (krōōg´mən), 1953–, American economist, b. Long Island, N.Y., grad. Yale (B.A., 1974), Massachusetts Institute of Technology (Ph.D., 1977). A founder of the "new trade theory," Krugman beginning in 1979 conducted research into international trade patterns, explaining why certain goods are produced in certain places, with trade mainly occurring between relative equals. In the 1990s he worked in economic geography, analyzing how transportation costs and various other forces affect where companies locate and workers live. It was this work that was largely responsible for his winning the 2008 Nobel Memorial Prize in Economic Sciences. His later academic research has concentrated on international finance and currency crises. Krugman has taught at Yale (1977–80), Massachusetts Institute of Technology (1984–94; 1996–2000), Stanford (1994–96), and Princeton (2000–). An economic and political liberal with an entertaining prose style, he has written essays for several print and online periodicals, e.g., Slate and Fortune, and since 2000 has been an op-ed columnist for the New York Times. Extremely prolific, he has also written hundreds of academic papers and more than 20 books, from economic texts to best sellers. Among the latter are The Return of Depression Economics (1999, upd. ed. 2009), The Great Unraveling (2003), and The Conscience of a Liberal (2007).