We have used this book, manuscript form, as supplemental reading in our environmental engineering classes at Duke University. The discussion of ethics is usually reserved for the final few days of class, when the students should start asking 'so what? about course material. We respond to this question by covering the principles of ethics in one lecture and spending two or more sessions discussing various readings. Engineering students who have spent four years learning how to crunch numbers and to solve technical problems to three significant figures admit that the study of environmental ethics introduces new and exciting concepts into their professional thinking, and provides a perspective which otherwise would be missing from their education.