Our attempts to establish robustness took two tacks. First, we showed that our results did not depend on the simple technical specifications of the model. This was tedious, and we have excised most of the details from the present version. The reader interested in analysis of the effects (distinctly minor) of changing our assump- tions that individuals are alike in all respects save their accident probabilities, that there are only two kinds of customers, and that the insurance market lasts but a single period, is referred to earlier ver- sions of this paper.7 An assessment of the importance of the as-
7. See Rothschild and Stiglitz (1975). One curious result of these investigations should be mentioned. In other areas of economic theory where existence of equilibrium has been a problem, smoothing things by introducing a continuum of individuals of