"Inequality in access to health care services, through private purchase, appears to pose policy challenges greater than inequality in other spheres. This paper explores how inequality in access to health care services relates to social welfare. I examine the sources of private demand for health insurance and the ramifications of this demand for health, for patterns for government spending on health care services, and for individual and social well-being. Finally, I evaluate the implications of a health tax as a response to the externalities of health service consumption, and provide a rough measure of the tax in the context of the Canadian publicly-financed health care system"--National Bureau of Economic Research web site.