This booklet for children emphasizes the exploration and protection of the environment. An introduction discusses the interaction between humankind and the environment, emphasizing that the earth is a closed system. Chapter 1, "Mission: Protect the Water," addresses human dependence on water, water pollution, and water treatment. Chapter 2, "Mission: Protect the Air," contains information on air pollution, air pollution abatement, and relatively new problems such as acid rain and radon gas in homes. Chapter 3, "Mission: Protect the Land," deals with hazardous wastes and solid wastes. Chapter 4, "Mission: Safer Use of Pesticides," discusses the use of pesticides on farms and around the home, the resistance or "R" factor, and how to protect oneself from pesticides. Chapter 5,"Mission: Safer Use of Toxic Substances," looks at the problem of what constitutes unsafe dosages of toxic substances and provides a toxic "hit list." Throughout the booklet are information, experiments, activities, and questions and answers about the topic at hand. The appendices include information about the Environmental Protection Agency (EPA) and federal and state laws, and a glossary of terms. (TW)