Market Potential and Global Growth over the Long Twentieth Century 1 1We are grateful to Shubhasish Barua and Mariela Dal Borgo for excellent research assistance and to Jules Hugot for providing us with French historical trade data. We thank Clifford Bekar and Benjamin Bridgman for helpful comments. We are also grateful for constructive comments by the editor and two referees. We also appreciate feedback from presentations at the 2015 AEA/TPUG Meeting, the 2016 Rocky Mountain Empirical Trade Conference, the 2016 St. Gallen Economic History and Trade Workshop, the 2016 CEPR Economic History Symposium, the 2016 Western Economic Association Conference, and Université Paris-Dauphine. We gratefully acknowledge research support from the Centre for Competitive Advantage in the Global Economy (CAGE) at the University of Warwick and the Social Sciences and Humanities Research Council of Canada. Jacks: Simon Fraser University and NBER, djacks@sfu.ca. Novy: University of Warwick, CEPR, CAGE, Centre for Economic Performance/LSE and CESifo, d.novy@warwick.ac.uk.