This work looks at the effects of xenobiotics (pollutants) on fish. It reviews the literature and uses to construct a conceptual model linking pollution impacts at the hierarchic levels of organization, from molecular to population and socio-economic, enabling the reader to understand more precisely the consequences of pollutants in the environment. Contributions from internationally-known and respected contributors have been drawn together to provide a reference that should find a place on the shelves of all those working in these areas.