Our analysis, and our conclusions, extend beyond the simple insurance market described above. The models of educational screening and signaling studied by, among others, Arrow (1973), Riley (1975), Spence (1973, 1974), and Stiglitz (1971, 1972, 1974a, 1975b), are obvious examples. The other papers in this symposium describe models that can be profitably studied using our techniques and our concepts. Models in which communities choose the level of public goods and individuals choose among communities on the basis of the menu of public goods and taxes that the different communities offer, provide a less obvious but, we think, important case.9