The predecessor to this book originated in the 1970s as notes to a junior/senior level course in "Chemistry of the Environment" that the authors developed at Rensselaer Polytechnic Institute in response to the interest in environmental concerns developing at that time. The present volume is an updated and expanded version of the original book published in 1978 and used ever since. Major changes in environmental problems have occurred in the years since the publication of the first edition, including the ozone and global warming concerns, the nuclear power plant meltdown at Chernobyl in 1986, and the world's worst oil spills in Kuwait and the Persian Gulf in 1991.