This book provides a state-of-the-art overview of the development of concepts and methodology of hydrological sys­ tems analysis and its wide range of practical applications. Hydrological systems analysis involves the management, processing and interpretation of huge amounts of geoscien­ tific as well as ecological and historical data of many different types and sources, which can only be handled coherently and efficiently by using interactive geoscientific information systems. Geoscientific information systems as well as flow simulators are integral parts of the methodology. The methodology is clearly explained in the book and ample figures il­ lustrate the text. The emphasis of the book is on the practical applicability of hydrological systems analysis in integrated water re­ source management, nature conservation and environmental planning. The compilation of many case-studies, conducted by TNO geohydrologists and others in recent years, included in the book deals with different temporal and spatial scales and various geohydrological settings in The Netherlands, Poland, the European Union as well as in Indonesia. These case studies underpin the strength and elegance of hydrological systems analysis.