This document defines what students should know and be able to do in order to be environmentally literate. It is a guide for building a curriculum from pre-kindergarten to adult levels that should enable the learner who has mastered it to make informed environmental decisions. Educators in schools, environmental learning centers, higher education institutions, agencies, and nonprofit organizations can use this book for curriculum development and adaptation. It can also be used to measure how well students are doing in achieving environmental literacy. Environmental literacy benchmarks, key systems concepts, and supporting concepts are provided as the framework for developing successful environmental education in working towards environmentally literate individuals and societies. (KHR)