Epidemiology is the study of the distribution of health outcomes and their determinants in populations and its application to prevent and control disease. This course introduces principles and methods of epidemiologic investigation and epidemiology¿s role in public health. Differences between experimental studies and observational studies in free-living human populations will be examined, followed by explanations of descriptive epidemiology, methods for measuring occurrence of risk factors and health outcomes, epidemiologic study designs, and analyzing and interpreting epidemiologic data. A variety of exposures and health outcomes will be used as examples to demonstrate the broad application of epidemiology in assessing and addressing public health problems.