This edition includes comprehensive chapters on the nature and uses of epidemiology; the epidemiological approach to defining and measuring the occurrence of health-related states in populations; the strengths and limitations of epidemiological study designs, causation, the contribution of epidemiology to the prevention of disease, the promotion of health and the development of health policy, and the role of epidemiology in evaluating the effectiveness and efficiency of health care. It enables students to describe the common causes of death, disease and disability in her or his community; outline appropriate study designs to answer specific questions concerning disease causation, natural history, prognosis, prevention, and the evaluation of therapy and other interventions to control disease, and critically evaluate the literature.