The book integrates for the first time existing ecosystem theories and is therefore able to present a full ecological and theoretical pattern. It shows that we are able to understand ecosystems and their reactions, provided that we use all basic systems ecology for different aspects of ecosystem properties. The first edition of this book was published in 1992. This second edition contains the many recently published and presented contributions on ecosystem theories, which show even more strongly that an integration of the existing ecosystem theories is needed and also possible.