American economist, Nobel laureate (2008), Distinguished Professor at CUNY's Graduate Center (after a long career at MIT and Princeton), and for twenty-five years the most widely read Keynesian public intellectual in the world through his twice-weekly column at The New York Times. Krugman is an unusual combination: a mathematical economist whose technical work reshaped two fields (international trade and economic geography), and a political commentator whose newspaper writing reaches an audience orders of magnitude larger than most of his peers ever address.
The Nobel recognized his new trade theory, developed in the late 1970s and 1980s, which showed how increasing returns to scale and imperfect competition — rather than the comparative-advantage assumptions of classical trade theory — explain much of modern international trade, and why countries that look similar trade intensively in similar goods. The follow-on work in new economic geography (collected in Geography and Trade (1991) and The Spatial Economy (1999, with Fujita and Venables)) applied similar tools to the clustering of economic activity across regions and cities. Both fields have become parts of the standard economist's toolkit.
From the late 1990s onward Krugman turned increasingly to public writing. The Return of Depression Economics (1999, revised 2009) was a prescient argument that the macroeconomic problems most economists thought had been solved — liquidity traps, deflationary spirals, the inadequacy of monetary policy at the zero lower bound — had reappeared in Japan and might return to the advanced economies. The 2008 financial crisis vindicated the thesis; End This Depression Now! (2012) made the Keynesian case for aggressive fiscal stimulus against the austerity consensus that had captured European and much of American policy. His New York Times column — and his textbook (Economics, with Robin Wells) — have, across two decades, done more than any other single body of writing to keep the case for active fiscal policy, social insurance, and regulated markets in front of a general American audience through the years when orthodoxy ran the other way.