The most difficult thing about writing a broad, introductory text like this is incorporating all the interesting and important material, keeping it current, and still resisting the temptation to let it grow to encyclopedic size. By careful pruning, I've managed to add significant new features to each edition of this book while still maintaining a reasonable length. I have had the good fortune in working on this revision to have more than 100 reviews from colleagues at colleges and universities across North America. They've offered many useful criticisms and suggestions for improving the book. If you are one of those reviewers, my most sincere thanks.

• A new introductory chapter presents suggestions to students about why environmental science is interesting and useful, how to study, how to prepare for tests, critical thinking, and concept maps. These topics are presented in the beginning of the book so students can begin to use them immediately. This is the kind of information that most of us cover in the first lecture of a class. No other book goes into the fundamentals of critical thinking theory and application found here.
• The other new chapter, Environmental Policy, Planning and Law, begins with a discussion of the policy cycle of agenda setting, problem definition, implementation, and evaluation by which public policy is established. The environmental law section defines statutory, case, and administrative law, a level of sophistication never before presented in an environmental science textbook. Also included are current concepts such as alternative dispute resolution, wicked problems, resilience in ecosystems and institutions, the precautionary principle, arbitration and mediation, and collaborative approaches to community-based planning. If our students are going to be educated environmental citizens, they need to know how these processes work.

• Every chapter in this book begins with a case study designed to introduce the main topic and pique student interest. Three quarters of these case studies are new to this edition and most are based on very recent news stories to emphasize the currency of environmental issues. All of them have been expanded from previous versions to be more substantive and meaningful. Overall, the total number of boxed readings have been reduced in this edition so that the remaining ones can be more substantial.

• Because critical thinking has been moved from Chapter 2 (Environmental Ethics and Philosophy) to the new Introductory Chapter, space is now available to present environmental ethics in greater detail. Notice that this discussion takes a pluralist approach. There is no prescribed "earthmanship ethics" that divides the world into bipolar camps. A variety of worldviews and ethical perspectives are presented and students are invited to think for themselves. Similarly the discussion of science isn't limited to positivist, reductionist, approaches, but recognizes the validity of descriptive and interpretive sciences.

• Chapter 8 (Ecological Economics) has been revised to include a major new section on green business, eco-efficient economy, the Natural Step movement, and "design for the environment." These topics are both very current and also positive examples of what we can do to improve environmental quality.

• Throughout the book data has been updated in tables, graphs, figures, and the text copy itself.
• Chapter 9 (Environmental Health and Toxicology) has a new treatment of infectious diseases that emphasizes emergent diseases and how drug resistance is selected for in microorganisms.
• Major revisions and corrections have been incorporated in Chapter 16 (Environmental Geology) including new information on earthquakes and flooding, and a new opening case study, "Earthquake in Turkey."
• Chapter 17 (Air, Climate, and Weather) has an informative new diagram on how tornadoes form, and a new diagram and discussion on El Nino/Southern Oscillations.
• Chapters 19 (Water Use and Management) and 20 (Water Pollution) have been updated with new data and current information.
• Chapter 21 (Conventional Energy) opens with a case study about the potential for a vast new oil supply under and around the Caspian Sea and how that affects regional politics, including the war in Chechnya.
• An important section has been added to Chapter 22 (Sustainable Energy) on the current topics of fuel cells and hybrid gas/electric automobiles.
• Much new and/or corrected material appears in Chapters 23 (Solid, Toxic, and Hazardous Waste), such as international toxic shipping, and 25 (What Then Shall We Do?). Chapter 25 now focuses much more succinctly than in the past on ways we can work individually and cooperatively to build a better world.