With a modular organization and a beautiful four color art program, the fourth edition of this leading text for non-majors continues to provide a clear presentation of the principles of ecology and illustrate their relation to today's environmental issues. Far-reaching in its coverage, the fourth edition provides the most up-to-date information with a new chapter on global warming and deforestation. It also focuses on ecology as a science, providing the basic background information needed to show the relevance of studying environmental problems on a global scale. A new supplement package-including an InstructorÕs Manual, printed and computerized test banks, and a four-color transparency acetate set-further strengthens the fourth edition as an excellent teaching tool for non-majors ecology courses.