Health Expenditure and Basic Models of Health Systems. The first part of this monographic study deals with the problems concerning health expenditure in industrialized countries (on average, 8% of home product in the countries belonging to Organization for Cooperation and Economic Development). The Author analyzes the structural factors causing the increase of health expenditure such as a population aging, scientific and technological progress, gap between consumption and expenditure, and demand for health service. The Author finally takes into consideration the two basic models of health systems, the solidarity model, born and widespread in Europe, and the individualistic model, mainly widespread in the U.S.A. The second part of the monographic studies deals with the evolution of the Italian Health System from the introduction of the National Health Service to the managerial reform. In particular, the authors analyze the mechanism of health planning, the financial support of the Italian Ministry of Health and the organization of health enterprises.