This book is organized around the three parts of the biosphere: land, water, and air. Each section contains descriptions of the environmental problems associated with that part of the biosphere. In the section on the atmosphere, for instance, such problems as acid rain and the greenhouse effect are discussed. Immediately following each problem or "challenge" are suggested ways that individuals can help solve or alleviate them. This book has been written to provide the reader with some easy and practical ways to protect the Earth, and to help understand why the task is so important.