This paper reviews Paul Krugman's fundamental contributions to new trade theory (NTT) and new economic geography (NEG) on the occasion of his 2008 Nobel Prize. We appraise the impact his work had on the field of regional science broadly defined, and we quantify its influence on papers published in Papers in Regional Science (PIRS) between 1991 and 2009 (vols. 70-87 and papers in press). We then discuss in more detail a few contributions published in PIRS that extend his original analysis in various directions. Finally, we briefly speculate on where NEG is headed to and which are the research directions that should be explored more thoroughly in the future.