Public health is about protecting and improving the health of whole populations and communities. Its motivation is to improve the health of individual people. Public health emphasizes the promotion of health and the prevention of disease and disability; the collection and use of epidemiological data; population surveillance and other forms of empirical quantitative assessment; a recognition of the multidimensional nature of the determinants of health; and developing effective solutions to population health problems. Many people do think of health, primarily, as the absence of disease. Diagnosing and treating disease is the central focus of most health systems, and at the core of traditional medical school curricula. While governments' approaches to public health often vary according to political outlook, it is the role of the public health professions and the bodies that represent them to establish the concepts, principles and methods of public health and, to some extent, to be custodians of the flame.