About the cover: Death Valley, one of the hottest places on Earth and home to more than 1000 species of plants, including more than 50 endemics, received record amounts of rain during the winters of 2004 and 2005. Through March of 2005, more than 8 inches of rain fell—4 times the yearly average of only 1.96 inches. Dormant seeds of various desert flowers germinated and flourished at record levels. This photograph was taken during one of these record rainfalls in March 2005. “One of the strengths of Masters/Ela is that the text is easily readable by undergraduate students who do not already have much background in environmental engineering and science. The writing style is clear and engaging.” Bruce E. Rittman, Arizona State University “This is one of the clearest and best written textbooks I have used. The text is concise and informative with a minimum of technological jargon…. I know that I could not be as effective an educator without well written and thoughtful textbooks such as Introduction to Environmental Engineering and Science.” Gail Montgomery Brion, University of Kentucky “The best features of this text are its readability and clarity. Secondly, its use of the mass balance approach, and carrying it throughout the rest of the book, is a great strength as well.” Gregory G. Wilbur, Oklahoma State University.