The protection of groundwater resources has emerged in recent years as a high priority topic on the agenda of many countries. In responding to the growing concern over deteriorating groundwater quality, many countries are developing a comprehensive regulatory framework for the management of subsurface water resources with management referring to both quantity and quality aspects. Within this framework, groundwater models are rapidly coming to playa central role in the development of protection and rehabilitation strategies. These models provide forecasts of the future state of the groundwater aquifer systems and/or the unsaturated zone in response to proposed management initiatives. For example, models will predict the effects of implementing a proposed management scheme on water levels and on the transport and fate of pollutants. The models are now used in the formulation of policies and regulations, the issuing of permits, design of monitoring and data collection systems, and the development of enforcement actions. The growth in the use of these sophisticated tools has led to many unforeseen problems in groundwater management. Lingering issues include reliability of codes, quality assurance in model development and applications, efficient utiliza tion of human and material resources, technology transfer and training. Some issues have legal ramifications, as in cases where the applications of models have been contested in courts."

ACKNOWLEDGEMENTS IX PART I CONFERENCE SUMMARY STATEMENT R. W. BROCKSEN, W. CHOW, E. D. DAUGHERTY, Y. G. MUSSALLI, J. WISNIEWSKI and A. L. WOODIS I Clean Water: Factors that Influence its Availability, Quality and its Use: Summary of the International Water Conference 3-7 PART II WATER RESOURCE OVERVIEWS S. PECK I Managing and Protecting Our Water Resources 11-20 R. BROCKSEN, W. CHOW and K. CONNOR I Addressing Electric Utility Surface Water Challenges 21-29 C. LOHSE-HANSON I Lake Superior Binational Program: The Role of Electric Utilities 31-40 J. A. VEIL and D. O. MOSES I Consequences of Proposed Changes to Clean Water Act Thermal Discharges 41-52 PART III ECOLOGICAL I HEALTH RISKS c. SEIGNEUR, E. CONSTANTINOU and L. LEVIN I Multipathway Health Risk Assessment of Power Plant Water Discharges 55-64 C. W. CHEN, J. HERR, R. A. GOLDSTEIN, F. J. SAGONA, K. E. RYLANT and G. E. HAUSER I Watershed Risk Analysis Model for TVA's Holston River Basin 65-70 S. FERSON, L. R. GINZBURG and R. A. GOLDSTEIN I Inferring Ecological Risk from Toxicity Bioassays 71-82 C. ARQUIETT, M. GERKE and I. DATSKOU I Evaluation of Contaminated Groundwater Cleanup Objectives 83-92 G. L. BOWIE, J. G. SANDERS, G. F. RIEDEL, C. C. GILMOUR, D. L. BREITBURG, G. A. CUTIER and D. B. PORCELLA / Assessing Selenium Cycling and Accumulation in Aquatic Ecosystems 93-104 D. W. RODGERS, J. SCHRODER and L.

Storage reservoirs represent one of the most effective tools for eliminating, or at least for minimizing, discrepancies in the time and space variations of water resources distribution and requirements. In fact, the different - often contradictory - and increasing demands on water resources utilization and control usually can be fulfilled only by building multi-purpose reservoir systems. In this way, the available water resources can be exploited and/or managed in a more rational way. Typically, the construction of a dam across a river valley causes water to accumulate in a reservoir behind the dam; the volume of water accumulated in the reservoir will depend, in part, on the dimensions of the dam. The size of the dam will normally affect the capital expenditure in a very significant way. Indeed the construction of large water resource control systems - such as dams - generally involves rather huge manpower and material outlays. Consequently, the elaboration of effectual methods of approach that can be used in establishing the optimal reservoir parameters is of great practical significance. For instance, in the design and operation oflarge multi-reservoir systems, simple simulation and/or optimization models that can identify potentially cost effective and efficient system design are highly desirable. But it should be recognized that the problem of finding optimal capacities for multi-reservoir systems often becomes computationally complex because of the large number of feasible configurations that usually need to be analyzed."

The irrigated area in the Aral Sea basin totals about 7. 5 million hectare. Part of the water supplied to this area is consumed by the irrigated crop; the remainder of the supplied water drains to the groundwater basin, to downstream depressions, or back to the rivers. During its use, however, this drained part of the water accumulates salts and chemicals. The disposal of this polluted water causes a variety of (environmental) problems. If the percentage consumed water of the total water supply to an irrigated area (the so-called overall consumed ratio) can be increased, less water needs to be drained. This alleviates part of the related (environmental) problems. Further, if the overall consumed ratio for the above 7. 5 million hectare is improved, less water needs to be diverted from the rivers. Hence, more water can flow towards the Aral Sea. As mentioned above, part of the non-consumed irrigation water drains to the groundwater basin. Commonly, the natural discharge capacity of this basin is insufficient to handle this imported water. As a result, the groundwater table rises towards the land surface causing waterlogging. In (semi-)arid zones this waterlogging triggers a soil salinity problem resulting to a significant reduction in crop yields. The artificial increase of the discharge capacity, and lowering of the groundwater table, solves the soil salinity problem.

This text is the first international and comprehensive discussion of the impacts of climatic fluctuations and climate change on water resources management. The book presents an overview of the impacts of climatic change/fluctuations on a wide variety of water resources sectors including river runoff, water quality, water temperature, water use and demand, reservoir management and water resource planning and management. The book is unique in that it then presents a series of case studies to both demonstrate the application of climate change impact assessment methodologies and to provide insights to catchment, river basin, and national scale impacts of climate change/fluctuations on the water resources of Africa, Europe, and North America. Audience: Researchers, scholars and students of hydrology and water management who are concerned with the issues of climate change as well as the climate change impact assessment community.

Next to air, water is the most essential of human requirements. The hydrosphere-the waters of the Earth, its oceans, rivers and lakes-is vital, constituting a feature unique in the solar system and one responsible for physical and climatic phenomena characteristic of the planet. Water moves through the hydrologic cycle and runs the heat engine of the Earth, approximately 97% of it occurring in the oceans. These contain vast natural resources including abundant plant and animal life and they assist in cleansing the atmosphere by becoming the final repository of air and land pollutants of which many are man-made. Unfortunately their ability to do this is diminishing because of rising pollution by toxicants such as DDT, nuclear by-products such as strontium-90 and oil spills. The oceans contain huge quantities of various substances mostly originating from the atmosphere, biological activity, river transport after rock weathering, groundwater, spreading zones along mid-oceanic ridges and crustal out-gassing. After hydrogen and oxygen, the commonest elements in them are Cl, Na, Mg, S, K, Ca, Br, C and B. The atmosphere and the oceans together cooperate in an energy cycle important in controlling and equalising the Earth's surface temperature.

This book is written primarily for Earth scientists faced with problems in thermo mechanics such as the flow and evolution of ice-sheets, convection currents in the mantle, isostatic rebound, folding of strata or collapse of cavities in salt domes. Failure, faults, seismic waves and all processes involving inertial terms will not be dealt with. In general such scientists (graduate students beginning a Ph. D. for instance) have too small a background'in continuum mechanics and in numerical computation to model conveniently these problems, which are not elementary at all. Most of them are not linear, and therefore seldom dealt with in treatises. If the study of reality were clearly cut into two successive steps: first to make a physical model, setting up a well-posed problem in thermo-mechanics, and second to solve it, the obvious solution would be to find a specialist in computational mechanics who could spend enough time on a problem which, although maybe crucial for on-going fundamental research, has little practical interest in general, and cannot be considered properly as a noteworthy progress in Mechanics. But this is not the way Science develops. There is a continuous dialectic between the building up of a model and its mathematical treatment. The model should be simple enough to be tractable, but not oversimplified. Its sensitivity to the different components it is made of should be investigated, and more thought is needed when the results contradict hard facts.

In recent years, much concern has been expressed on the deleterious effects that anthropogenic emissions of acidic pollutants have on ecosystems of both industrialized countries and remote areas of the world. In many of these regions, seasonal snowcover is a major factor in the transfer of atmospheric pollutants, either to terrestrial and aquatic ecosystems or to the more permanent reservoirs of glaciers and ice sheets. The recognition of the role that seasonal snowcovers can thus play in the chemical dynamics of whole ecosystems was recently echoed by the Committee on Glaciology of the National Research Council (National Academy of Sciences, National Academy of Engineering and the Institute of Medicine) which recommended that studies on "Impurities in the snowpack, their discharge into runoff, and management of the problem" be rated at the highest prority level (ref. a). It is in this context that the Advanced Research Institute (ASI) brought together scientists active in the fields of snow physics, snow chemistry and snow hydrology. The programme was structured so as to facilitate the exchange of information and ideas on the theories for the chemical evolution of seasonal snowcovers and snowmelt and on the impact of the chemical composition of the meltwaters on the different components of hydrological systems. As a consequence the ASI also attracted participants from potential users of the information that was disseminated; these were particularly concerned with the effects of snowmelt and snowcover on terrestrial biota and those of lakes and streams.

Floods constitute a persistent and serious problem throughout the United States and many other parts of the world. They are responsible for losses amounting to billions of dollars and scores of deaths annually. Virtually all parts of the nation--coastal, moun tainous and rural--are affected by them. Two aspects of the problem of flooding that have long been topics of scientific inquiry are flood frequency and risk analyses. Many new, even improved, tech niques have recently been developed for performing these analyses. Nevertheless, actual experience points out that the frequency of say a IOO-year flood, in lieu of being encountered on the average once in one hundred years, may be as little as once in 25 years. It is therefore appropriate to pause and ask where we are, where we are going and where we ought to be going with regard to the technology of flood frequency and risk analyses. One way to address these ques tions is to provide a forum where people from all quarters of the world can assemble, discuss and share their experience and expertise pertaining to flood frequency and risk analyses. This is what con stituted the motivation for organizing the International Symposium on Flood Frequency and Risk Analyses held May 14-17, 1986, at Louisiana State Universj. ty, Baton Rouge, Louisiana."

Reservoirs for Wastewater Storage and Reuse is a compendium of available information on this emergent technology, from the role that wastewater reservoirs can play within general water resources management and wastewater reuse policy, to the design and operation of the units, including removal efficiencies for different pollutants. Furthermore, a detailed description of the ecological structure and function of the ecosystem of reservoirs is given. This book summarizes more than 20 years of research and development in Israel where more than 200 of these reservoirs are in operation. It includes both theoretical developments and practical experience gained by designers, operators and farmers. Potential geographic areas for the use of these reservoirs are the whole Mediterranean region, the Pacific coasts of both South and North America, the Atlantic coasts of Africa, the Middle East, and other regions suffering water shortage.

Remote sensing is the study of a region from a distance, particularly from an airplane or a spacecraft. It is a tool that can be used in conjunction with other methods of research and investigation. This tool is especially applicable to the study of the deserts and arid lands of the Earth because of their immense size and their inaccessibility to detailed study by conventional means. In this book examples are given of the utility of aerial photographs and space images in the study of semi-arid, arid, and hyper-arid terrains. Emphasis is placed on the physical features and terrain types using examples from around the world. The authors I have called upon to prepare each chapter are renowned specialists whose contributions have received international recognition. To the general reader, this book is a review of our knowledge of the relatively dry parts of the Earth, their classification and varied features, their evolution in space and time, and their development potentials. To the specialist, it is a detailed account of the deserts and arid lands, not only in North America, but also their relatively unknown counterparts in North Africa, Australia, China, India, and Arabia.

Advances in computer technology, in the technology of communication and in mathematical modelling of processes in the hydrological cycle have recently improved our potential to protect ourselves against damage through floods and droughts and to control quantities and qualities in our water systems. This development was demonstrated in a 1983 post-experience course at Wageningen University where an international group of experts reviewed successful modelling techniques and described the design and operation of a number of forecasting and control systems in drainage basins and river reaches of various sizes and under various geographical and climat ological conditions. A special effort was made to bridge the gap between theory and practice; case studies showed that each forecasting system was designed to meet a set of specific requirements and they illustrated that the forecasting system can only be expected to operate reliably if, on the one hand, it is based on sound theoretical concepts and methods and if, on the other hand, it is robust so that, also under adverse conditions, it will continue to collect and process the necessary input data and produce correct and timely signals. We were pleased to meet with encouragement for preserving the course material and making it available to a wider public. This was effected by the team of authorf who elaborated, updated and harmonized the materia in two stages; first into an issue of our university department and finally into the manuscript of this book."

stable or falling water levels, and permit differen tiation between gradual and sudden transgression The level of Lake Ontario was long assumed to of the shoreline. Vegetational succession reflects have risen at an exponentially decreasing rate shoreline transgression and increasing water solely in response to differential isostatic rebound depth as upland species are replaced by emergent of the St. Lawrence outlet since the Admiralty aquatic marsh species. If transgression continues, Phase (or Early Lake Ontario) 11 500 years B. P. these are in turn replaced by floating and sub (Muller & Prest, 1985). Recent work indicates merged aquatic species, commonly found in water that the Holocene water level history of Lake to 4 m depth in Ontario lakes, below which there Ontario is more complex than the simple rebound is a sharp decline in species richness and biomass model suggests. Sutton et al. (1972) and (Crowder et al., 1977). This depth varies with Anderson & Lewis (1982, 1985) indicate that physical limnological conditions in each basin. periods of accelerated water level rise followed by Because aquatic pollen and plant macrofossils are temporary stabilization occurred around 5000 to locally deposited, an abundance of emergent 4000 B. P. The accelerated water level rise, called aquatic fossils reflects sedimentation in the littoral the 'Nipissing Flood', was attributed to the cap zone, the part of the basin shallow enough to ture of Upper Great Lakes drainage. support rooted vegetation."

The possible impacts of global climate change on different countries has led to the development and ratification of the Framework Convention on Climate Change (FCCC) and has a strong bearing on the future sustainable development of developing countries and countries with economies in transition. The preparation of analytical methodologies and tools for carrying out assessments of vulnerability and adaptation to climate change is therefore of prime importance to these countries. Such assessments are needed to both fulfill the reporting requirements of the countries under the FCCC as well as to prepare their own climate change adaptation and mitigation plans. The vulnerability and adaptation assessment guidelines prepared by the U.S. Country Studies Program bring together all the latest knowledge and experience from around the world on both vulnerability analysis as well as adaptation methodologies. It is currently being applied successfully by scientists in over fifty countries from all the regions of the globe. This guidance is being published to share it with the wider scientific community interested in global climate change issues. This guidance document has two primary purposes: * To assist countries in making decisions about the scope and methods for their vulnerability and adaptation assessments, * To provide countries with guidance and step-by-step instructions on each of the basic elements of vulnerability and adaptation assessments.

The completion of this collection took many months, and, for a variety of reason, required the assistance and/or indulgence of a number of individuals. First and foremost, I would like to thank Tim Hudson for his useful input and support at the outset of the project Likewise, I would like to thank Jesse O. McKee for providing a hospitable environment during my affiliation with the University of Southern Mississippi. At Louisiana State University I am grateful to Sam Hilliard and Carville Earle for their invaluable understanding. The book became part of the GeoJoumal Library as a result of Wolf Tietze's confidence in the topic, and because of Henri G. van Dorssen's (and Kluwer Academic Publishers') good nab.lre - despite numerous 'problems'. Curtis C. Roseman, and the remainder of the Geography Department at the University of Southern California (where I completed many last minute details for the volume), are to be thanked for the cordial and warm environ ment I received while a visitor in Los Angeles. Finally, no multi-authored collection reaches completion without the help of many patient contributors. This particular book suffered many set-backs along the way, so I am particularly grateful to the authors herein. They demonstrated their compassion and exceptional professionalism throughout, by never second-guessing my decisions, and by allowing me to remedy the set-backs in my own way. They were a pleasure to work with, and they should take pride in their achievements."

This volume certainly is a Conference Proceedings, the Proceedings of the NATO Advanced Research Workshop (ARW) on "Unsaturated Flow in Hydrologic Modeling" held at "Les Villages du Soleil" near ArIes, France from June 13 to 17, 1988. Let me therefore acknowledge properly, at the very beginning, the gratitude of all the participants to the NATO Science Committee for its generous support and worthwhile goal of bringing together scientists of many countries to communicate and share their experiences. Particular thanks are extended to the director of the program, Dr. Luis Vega da Cunha for his interest and understanding. On the other hand this volume is also, and probably more so, a Textbook that fills a gap in the field of unsaturated flow. Many treatises on the subject present the theory in its different aspects. Hardly any explain in details how the different pieces can be put together to address realistic problems at the basin scale. The various invited contributions to the ARW were structured in a subject progression much as chapters are organized in a book. The intent of the ARW was to assess the current state of knowledge in "Unsaturated Flow" and its use in "Hydrologic Modeling Practice." In a sense the interest in fundamentals of unsaturated flow in this ARW was not just for the sake of knowledge but also and primarily for the sake of action. Can such fundamental knowledge be utilized for better management of the water resource? was the basic question.

Causes of major disasters are many and diverse, and the risks associated with them endanger human lives, property, the environment, the economy, and even the country's political and social well-being. It is clear that, with rapid population growth, environmental degradation, climate change, poorly regulated industries, and continued economic uncertainty, the chances are that communities may become more vulnerable to disasters. The dramatic losses in recent years from volcanic eruptions, earthquakes and landslides, wildland fires, droughts and floods, cyclones and storm surges attest to the fact that we are still a long way from applying even the knowledge we have today to make communities safe. Tackling this problem requires a sound evaluation of disaster mitigation policies and tools. As a contribution to the International Decade for Natural Disasters Reduction (IDNDR), the fifth international symposium HAZARDS-93 was held in Qingdao, P.R. China on 29 August - 3 September, 1993. China is a country frequently hit by almost all kinds of disasters. Its history is one of combating natural disasters and working towards their reduction. More than 250 scientists, engineers and government officials from 20 countries met for the purpose of engaging in a free exchange of knowledge, experience and ideas regarding the scientific and socio-economic aspects of mitigating losses from natural and man- made disasters. A total of 180 papers were presented at 28 sessions covering a very broad range of topics related to disaster management. The twenty-one articles included in this book deal with the scientific and management issues of land-based and marine hazards which cause the most severe economic losses, deaths and environmental degradation in many parts of the world. The book also includes specific recommendations addressed to the IDNDR Secretariat, national governments and scientific experts to increase the effectiveness and efficiency of disaster management. Thus, Land-Based and Marine Hazards: Scientific and Management Issues forms an excellent reference for scientists, engineers, policy-makers and the insurance industry.

About four years ago Dr. Gilbert White visited China and sowed the seeds of this project through conversations with Drs. Huang and Gong of the Chinese Academy of Sciences, and Mr. Long of the Yellow River Conservancy Commission. After some additional rounds of communications by letter, the plan for a workshop evolved and Drs. Wolman and Brush visited with Dr. Sabadell of the Nat_ional Science Foundation to begin the initial planning. In March 1987 Dr. Brush visited China and the details were worked out for the October 1987 workshop. At the outset it was recognized that the 10 American scientists and engineers ltad very Ii ttle knowledge of the Yellow River and none had ever seen it. Therefore, it became important that field trips be scheduled before the workshop to better set the stage for fruitful discussions. It was also acknowledged that the American participants could not present papers about the Yellow River per se so their offerings reflected their general knowledge of rivers using other rivers as examples. On the other hand the Chinese participants were all well into the difficult problems of harnessing the Yellow River and made their presentations accordingly. Despite these differences the subject matter was the unifying thread and cross communication was excellent.

For centuries, physical models have been used to investigate complex hydraulic problems. Leonardo da Vinci (1452-1519) stated, "I will treat of such a subject. But first of all, 1 shall make a few experiments and then demonstrate why bodies are forced to act in this matter. " Even with the current advancements of mathematical numerical models, certain complex three-dimensional flow phenomena must still rely on physical model studies. Mathematical models cannot provide adequate solutions if physical processes involved are not completely known. Physical models are particularly attractive to investigate phenomena-involved sediment movements because many three-dimensional sediment processes are still unclear at this stage. Theoretically, there are numerous factors governing movable bed processes and it is nearly impossible to design model studies to obey all the model criteria. Sometimes, appropriate lightweight materials are difficult or too costly to obtain. Often, distorted models are used due to the limitation of available space and the requirement for greater vertical flow depth to investigate vertical differences of various parameters. The turbulence level in the model may also be maintained at a sufficient level to reproduce a similar flow pattern in the prototype. Frequently, engineers are forced to employ distorted models that cannot be designed to satisfy all governing criteria correctly. Thus each hydraulic laboratory has developed its own rules for model testing and a great deal of experience is needed to interpret model results.

In recent years, several major natural and man-made hazards have challenged scientists, government officials and the public in general: earthquakes, major volcanic and other seismic eruptions in Mount St. Helens, EI Chichon, Mexico city, Nevado del Ruiz, Japan, Italy, Greece, Cameroon and many other places on our globe; Tsunami in the Pacific Ocean and deadly storm surges along the coasts of India, Bangladesh and Japan; Cyclones, floods, thunderstorms, snow storms, tornadoes, drought, desertification and other climatic catastrophes; Amoco-Cadiz oil spill accident (France), Three-Mile Island (U. S. A. ) and Chernobyl (U. S. S. R. ) nuclear accidents, Bhopal chemical accident (India), acid rain (Canada, U. S. A. ) and other technological disasters. Such hazards have snuffed out millions of lives, infli

Desertification has re-emerged as a topic of global significance as a consequence of the United Nations Conference on Environment and Development. When first addressed over a generation ago, attention was drawn to the compelling, spectacular images of sand dunes engulfing farmlands and parched cattle dying around wells. Research tended to focus on these events as unusual phenomena that involved the unfortunate collision of climate and `irrational' land use. Since then, the work of many researchers has shown us that desertification is a multifaceted problem that involves climatic, biogeochemical, political, and socio-economic processes that operate more or less continuously but at rates that vary in time and space. No attempts to arrest or reverse desertification that ignore this complexity are likely to succeed. In a single volume, `Desertification in Developed Countries' describes the multiple dimensions of desertification as well as the novel approaches that have been used to address it within the economies of developed countries. This is done from the perspectives and experiences of the numerous authors who have contributed to this book.

The International Hydrological Decade (which ended in 1975) led to a revival of hydrological sciences to a degree which, seen in retrospect, is quite spectacular. This research programme had strong government support, no doubt due to an increased awareness of the role of water for prosperous development. Since water quality is an essential ingredient in almost all water use, there was also a considerable interest in hydrochemistry during the Decade. As many concepts in classical hydrology had to be revised during and after the Decade there was also a need for revising hydrochemistry to align it with modern hydrology. A considerable input of fresh knowledge was also made in the recent past by chemists, particularly geochemists, invaluable for understanding the processes of mineralization of natural waters. With all this in mind it seems natural to try to assemble all the present knowledge of hydrochemistry into a book and integrate it with modern hydrology as far as possible, emphasizing the dynamic features of dissolved substances in natural waters. Considering the role of water in nature for transfer of substances, this integration is essential for proper understanding of processes in all related earth sciences. The arrangement of subjects in the book is as follows. After a short introductory chapter comes a chapter on elementary chemical principles of particular use in hydrochemistry.

Earthquake Hazard and Risk is a book summarizing selected papers presented at the 27th General Assembly of the International Association of Seismology and Physics of the Earth's Interior (Wellington, January 1994). The papers, rigorously scrutinized by an international board of referees, cover some recent aspects of current research in earthquake hazard and seismic risk. They address the algorithms and methodology used in seismological applications, the reliability of these techniques with the decreasing level of probability and uncertainty associated with various seismotectonic settings, the physical and statistical nature of earthquake occurrences, strong ground motions and effects of surface seismogeological conditions. A special effort has been made to include papers that illustrate the assessment of earthquake hazard and seismic risk through applications at sites in either inter-plate or intra-plate tectonic settings. Of particular interest is hazard assessment in regions of rare large earthquakes. The book is suitable for those interested in earthquake hazard and seismic risk research as well as a more general audience of seismologists, geophysicists and Earth scientists. It is also useful for authorities responsible for public safety and natural hazard mitigation plans and for insurance companies.

Water is one of the world's threatened resources: it is also a substance of importance in Geology. For some years I have felt the need for a book that sets out the fundamentals of fluid mechanics, written for geologists rather than engineers. The efforts to repair my own deficiencies in this respect led me along various unfamiliar paths, few of which were unrewarding. This book is the result of my journeys through the literature and as a geologist in several parts of the world. It has been written for students of geology of all ages, in the simplest terms possible, and it has one objective: to provide a basis for an understanding of the mechanical role of water in geology. It has not been written for experts in ground water hydrology, or specialists in the fluid aspects of structural geology: it has been written for geologists like me who are not very good mathematicians, so that we can take water better into account in our normal geological work, whatever it might be. The fundamentals apply equally to mineralization, geochemistry, and vulcanology although they have not been specifically mentioned. It has also been written for the university student of geology so that he or she may start a career with some appreciation of the importance of water, and understanding of its movement."

More and more clinicians as well as researchers realize that anorexia nervosa and bulimia nervosa often are extremely difficult to treat and that the short-term outcome can be very misleading. In many cases these disordersprevail for a long period of time and can have serious consequences for the patient's further life. This book gives a detailed over- view oftoday's knowledge regarding the long-term outcome of the treatment of anorexic and bulimic patients, many of whom were treated in highly spezialized centers. Experts from bo- th Europe and the U.S. report on theirmost recent research. Their studies include medical as well as psychosocial and psychiatric aspects of eating disorders. Clinicians with long experience in the treatment of eating disorder patients discuss the important practical implications of these rese- arch findings. The information given in this book is helpful for both treatment and prevention of eating disorders. Finally, concrete guidelines show as how to conduct further follow-up studies in this field.