Relation of Profit Rate to Industry Concentration: American Manufacturing. 1936-1940 TORIo Joe s. bain The Quarterly Journal of Economics, VoL. 65, No. 3(Aug, 1951), 293-324 Stable url: http://links.jstor.org/sici?sici=0033-5533%028195108%02965%3a3%03c293%03aroprti%3e2.0.co%3b2-n The Quarterly Journal of Economics is currently published by The MIT Press Your use of the jStOR archive indicates your acceptance of JSTOR,'s Terms and Conditions of Use, available at http://www.jstor.org/about/terms.htmlJstOr'sTermsandConditionsofUseprovidesinpartthatunlessyou have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://wwwjstor.org/journals/mitpress.html Each copy of any part of a STOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission jStOR is an independent not-for-profit organization dedicated to creating and preserving a digital archive of scholarly journals. For more information regarding JSTOR, please contact support @ jstor. org http://wwwjstor.org Wed nov211:43:09200