This paper examines the structure of the American medical care system, especially the system of care for the elderly. We focus on three sets of interactions: coverage rules (how people get health insurance and who pays for it); the reimbursement system (how providers are paid); and access rules (what are the financial and nonfinancial barriers to receipt of care). Coverage in the United States is variable – guaranteed and complete for the elderly, but neither guaranteed nor complete for the nonelderly. Historically, reimbursement of providers was very generous, and access to providers was open. Increasingly, though, the reimbursement and access routes are being restricted, as insurers respond to the perception of significant moral hazard in the receipt of care.