The preliminary work on this book goes back to lectures and seminars which I held on the subject of an ecological division of the world at the Geographical Department ofthe Aachen University of Technology (RWTH Aachen). The idea of presenting this material in book form arose as I became aware that no modern compendium exists, in either German or English (or in any other language, as far as I know), which could have aided me in preparing these courses or would have helped the participating students to review the material presented in the classroom. Existing studies on major land ecosystems, some of which are highly de tailed, have been published over the past 15 years by firms such as the Springer Verlag (Ecological Studies), the Cambridge University Press (International Biological Programme) and the Elsevier Scientific Publishing Company (Ecosystems of the World); all suffer from the fact that individual aspects (mainly botanical-ecological ones) are given the utmost consideration, while other aspects (often pedological and geomorphological ones) are almost entirely neglected. Furthermore, it is most aggravating that the various studies have failed to establish consistent terminology, units of measurement, and organization of the data for all of the global ecosystems, thus making it difficult even for the knowledgeable reader to make comparisons. The individual nature of each ecozone therefore remains unclear, since it is precisely these differences that allow those characteristics peculiar to a specific ecozone to be unmistakably recognized.
