Paul Krugman has clarified the microeconomic underpinnings of both spatial economic agglomerations and regional imbalances at national and international levels. He has achieved this with a series of remarkably original papers and books that succeed in combining imperfect competition, increasing returns, and transportation costs in new and powerful ways. Yet, not everything was brand new in New Economic Geography. To be precise, several disparate pieces of high-quality work were available in urban economics and location theory. Our purpose in this paper is to shed new light on economic geography through the lenses of these two fields of economics and regional science