The environment profoundly affects the public's health. This course summarizes the concepts and principles underlying environmental health sciences, characterizes the major environmental agents and vectors affecting public health, and introduces major ecologic, scientific, and political issues from selected topical areas of environmental health. It presents the major concepts and principles that are environmentally mediated and that constitute a risk to humans emphasizing the chemical, biological, and physical agents and factors. Then, considers sources, environmental pathways of transmission, exposure-dose relationships, adverse health effects, and particularly susceptible populations. It identifies the principles and methods of risk assessment and risk management, and uses these as a unifying theme.