Epidemiology is the study of the distribution and determinants of health-related states and events in populations. It involves analyzing patterns of health and disease to inform public health policies and interventions. Understanding epidemiology is fundamental for identifying risk factors, controlling disease outbreaks, and improving population health outcomes. This book provides a foundational introduction to the principles and methods of epidemiology, covering key concepts such as study design, data collection, and statistical analysis used to investigate health patterns. It explores the application of epidemiological findings in developing public health strategies and policies aimed at disease prevention and health promotion.