This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book examines a variety of disturbances, Agriculture and domestic grazing are by far the greatest causes of desertification. It highlights an understanding and application of the basic ecological relationships among plants, animals, microorganisms, the physical environment and man to reconstruct useful, primarily wildland ecosystems. The book focuses on different initial conditions that may dictate the subsequent trajectory of succession. It is concerned with plant architecture and dispersion, where the pattern in which plants are introduced into a disturbed site specifically determines the microorganisms as well as hastening the rate of succession of the ecosystem as a whole. An ecological approach that enhances the processes of natural succession may also make reconstruction of more arid lands economically feasible. Disruption of the hydrologic cycle and its reconstruction by reintroduction of appropropriate plant species is Greenwood's theme.