Environmental toxicology is the study of the action of chemicals upon ecosystems. Understanding the effects of exogenous chemicals upon the inhabitants of an ecosystem may enable us to predict and possibly prevent their deleterious effects. This textbook provides a good general introduction to all the major areas of environmental toxicology, including the fate of chemicals in the environment, environmental toxicity testing, risk assessment, radioactivity in the environment, legislation, environmental monitoring and the future impact of industrial development on the environment. It is written in an informal, accessible style with many examples of environmental issues taken from the author's personal experience and will provide students and other interested individuals with a broad overview of the science of environmental toxicology.