Published previously as six separate books, this revised manual contains lesson plans for over 300 K-12 environmental education experiences. Four activity sections follow an introductory chapter on the philosophy, model, and implementation guidelines for the "people-environment interaction" perspective upon which these activities focus. The Concept Activities and Understandings section provides lessons on five major concepts basic to the development of environmentally literate citizens: ecosystem, population, economics and technology, environmental decisions, and environmental ethics. In the Skill Developing Activities chapter, experiences that foster development of eight environmental problem-solving skills are offered. Strategies to help students examine their environment-related values comprise the section on Values Clarification Activities. The Environmental Encounters section contains a series of activities for studying and solving environmental problems in schools and communities. Lessons in all four of these activity sections are identified by grade level. Concluding the manual is a chapter listing titles and sources of numerous environmental education resource materials. (WB)