Concepts of the human environment through a systems approach are presented. Principles of systems thinking which assist the student to study subjects with a comprehensive view of the way topics are interrelated with each other, rather than considering subjects in isolation, are discussed. Part One introduces systems concepts. Part Two deals with environmental systems, including ecosystems, economic systems, political systems, and their role in the human environment. Part Three provides appendices of system notes, sources for further study and a bibliography. (RE)