Studying animals in the environment may be a realistic and highly beneficial approach to identifying unknown chemical contaminants before they cause human harm. Animals as Sentinels of Environmental Health Hazards presents an overview of animal-monitoring programs, including detailed case studies of how animal health problems?such as the effects of DDT on wild bird populations?have led researchers to the sources of human health hazards. The authors examine the components and characteristics required for an effective animal-monitoring program, and they evaluate numerous existing programs, including in situ research, where an animal is placed in a natural setting for monitoring purposes.