Since the publication of the first edition of this volume in 1988, we have made great strides in reducing the amount of toxic waste that threatens our water, soil, and air. A greater acceptance of clean fuels and clean technologies, along with increased public awareness of environmental health hazards has given us greater optimism about the future of our planet. While few environmental threats can ever be completely eradicated, provides a framework for understanding the nature of hazardous materials and how the risks from such materials may be reduced.