Additionally, the structure and function of three important types of ecosystems are addressed, namely the seas, the lakes and the forests. The text is supported everywhere by instructional drawings. The book deals not particularly with pollution and environmental problems, which in many people's consciousness is almost synonymous with ecology, but touches on many such topics and provides the foundation for a basic understanding of many of today's urgent environmental problems. The author is Hans Ulrik Riisgård, Professor, PhD & DSc, Department of Biology, University of Southern Denmark, where he has taught general ecology and marine biology for many years.