This book describes the many ways in which epidemiological methods may be used to solve problems in family practice. Practicing physicians are concerned with understanding the incidence, prevalence, and natural history of symptoms of disease. They are also concerned with the factors which prompt ill individuals to seek medical assistance and which may help prevent healthy individuals from falling ill. The interpretation of symptoms and the use of diagnostic skills are likewise governed by knowledge of the probability of disease. Epidemiology provides the basis for making these decisions, and this book makes the principles and methods of epidemiology accessible to every doctor. It identifies many typical problems that can be addressed epidemiologically and describes the ways in which doctors may critically analyse these problems in order to provide solutions within the limits of available resources.