This review offers the quintessence of the knowledge necessary for the understanding of what public health represents and the future of public health. It integrates the new legislative and regulatory provisions of the health law, history and regulatory developments. It shows the evolution of the definition of public health, the organization of the hospital and the health system, the main actors and institutions in public health, all in a national and international approach. It is written in a simple, clear and precise structure. It will decipher many aspects of public health through indices and concepts such as clinical epidemiology, clinical reasoning as well as medical decision making, critical analysis of scientific and medical information. It also covers the methodology of experimental and clinical research, the interpretation of a survey, the analysis and use of results, health systems, prevention, health promotion and other important determinants of public health.