IN THE FALL OF 1942, as the Allied and Axis nations marshalled their forces for decisive battles at Guadalcanal, El Alamein, and Stalingrad, Joseph A. Schumpeter's Capitalism, Socialism, and Democracy (CSD) was published. Perceived by Schumpeter at the time as a little book of essays somewhat in the nature of a potboiler,' it distilled for the intelligent lay reader almost forty years' thought, observation, and research (1942, p. ix) by the Austrian economist-statesman-banker turned Harvard don. Fifty years later, it remains relevant. In particular, it brought into the main stream of economic discourse the question of what market structures were most favorable to technological change and hence economic growth. Both in the United States and abroad, policy debates over that issue persist. Schumpeter's conjectures on market structure, the work by economists to extend them, and the continuing policy puzzles are the main focus of this anniversay essay. II. The Challenge

Hence, even if the partial equilibrium analyst knows full well that the actual situation is not really a competitive one, he probably will still make a first try using the competitive model with good old-fashioned profit maximization. And if the results appear too odd, appropriate qualifications may still be able to take care of them more simply than if he had started with a cumbersome managerial model. (In saying this, I am showing my bias.) [18, p. 30]