This is an entry produced for the Handbook of the History of Economic Analysis, edited by Gilbert Faccarello and Heinz D. Kurz. Cheltenham, UK and Northampton, MA, USA: Edward Elgar, forthcoming.

In February 1933, Edward Chamberlin published The Theory of Monopolistic Competition. Joan Robinson's The Economics of Imperfect Competition followed in the spring. A disciplinary consensus quickly formed, holding that the two books represented simultaneous discoveries of the same theoretical...