An expert analysis of the various National Health Insurance options, with a focus on the areas in which the most serious gaps between policy and performance are likely to occur. A major problem, recognized by all, is that the objectives of N.H.I.--guaranteeing an adequate supply of medical services, encouraging high-quality care, restraining costs--will always conflict. What, then, would the effect be of narrow or wide coverage? of a minimal, a limited, or a large federal financial role? The answers draw on historical material from this country (how Medicare and Medicaid have inflated the cost of medical care), as well as on the experience of Canada and other countiies with actual N.H.I. programs. Special attention is paid to the public's doubts regarding efficacy and honesty of government programs--what the implications of failure would be and what policy choices would best help N.H.I. to attain its objectives. In looking at N.H.I. from this operational angle--asking not the merits of fee-for-service reimbursement, for example, but the ramifications--the contributors have shed considerable light on a complex question. An important source for all those immediately involved.