I. INTRODUCTION AND METHODS. 1. Epidemiology: What Is It About? 2. Some Useful Concepts in Epidemiology. 3. Rates: A Basic Epidemiological Tool. 4. Epidemiological Methods. 5. Epidemiological Transitions in Disease Patterns Over Time. 6. Epidemiology and Control of Diseases of Infectious Origin. 7. Epidemiology and Control of Diseases of Noninfectious Etiology. II. EPIDEMIOLOGY AND THE LIFE CYCLE. 8. Patterns of Morbidity and Mortality During Pregnancy and Infancy. 9. Patterns of Morbidity and Mortality in Childhood and Adolescence. 10. Patterns of Morbidity and Mortality in Young and Middle Adulthood. 11. Patterns of Morbidity and Mortality Over Age 65. III. APPLICATIONS OF EPIDEMIOLOGY. 12. Etiology and Natural History. 13. Disease Control and Surveillance. 14. Screening. 15. Clinical Decision Making. 16. Health Planning Evaluation.