Public health refers to the science and practice of preventing disease, prolonging life, and promoting health through organized efforts of society, communities, and individuals. It encompasses a broad range of activities, policies, and programs designed to protect and improve the health of populations rather than focusing solely on individual patients. Public health addresses the determinants of health, including social, economic, environmental, and behavioral factors, aiming to reduce health inequalities and enhance the quality of life for all people. It involves surveillance of disease, health promotion, education, policy-making, and interventions that target populations at risk. Unlike clinical medicine, which treats individuals, public health emphasizes prevention, population-based interventions, and the creation of health-supportive environments. The concept of public health has evolved significantly over time, reflecting changes in society, scientific knowledge, and the patterns of disease. Traditionally, public health was primarily concerned with controlling infectious diseases, ensuring sanitation, and providing clean water and proper waste disposal. In ancient and medieval societies, public health measures included quarantines during epidemics, regulation of food and water, and isolation of individuals with contagious diseases. These early efforts were often reactive, responding to outbreaks as they occurred, rather than being proactive in promoting health. With the advent of industrialization in the 19th century, public health began to expand its scope to address the conditions that affected large urban populations. The overcrowding, poor sanitation, and hazardous working conditions in