Chronological developments of public health in 19th and 21st centuries are discussed in this book, starting from Edwin Chadwick's sanitary movement and the social and Economic Drivers behind them,John snow's work and various legislative Acts. In 19th century the main focus was on Physical Infrastruture especially to provide adequate sanitation ,housing and clean water.Public Health then was mainly concerned with the prevention of Infectious and contagious threats to Human health and concerned with poor and special needs group. What has emerged as the New public Health is the approach which tries to bring together the environmental change and personal perspective measures with suitable interventions. The contemporary health problems is seen as social rather than individual and what is needed to address these problems is Healthy Public Policy. In the New public Health the environment is Social,psychological and physical as well. The desire for New Public Health movement to tackle the Health problems of 21st century found its expresionin WHO's Global strategy of Health for All by the year 2000(HFA2000).