Paul Krugman was a leading figure in the 1980s and 1990s MIT economics department and a giant in international economics. This chapter considers his outstanding contributions in the fields of trade, economic geography and international finance. I have also collected some biographical information. Krugman’s papers are notable for their particular style of framing and conducting research. I draw on his own reflections on his methods and add examples. The chapter concludes with a discussion of Krugman’s legacy in the fields cited in his 2008 Nobel Prize, namely trade and economic geography.