The maximum quantity of water on earth belongs to oceans - 96.5 per cent of the total. Only 0.2972 per cent of the total is freshwater, which is needed for meeting human needs, and it comes mainly from lakes, river flows and groundwater aquifers. These water systems perform numerous ecosystem services and support a great variety of ecosystem productivity, which are crucial for sustenance of the world population. We generally see water flowing out to the sea as water going waste. This has led to a water management system centred around dams. Water as a resource is really embedded in the ecosystem. We should not treat issues connected with water as manipulatable, since it would lead to chaos and disaster. In this book, Jayanta Bandyopadhyay highlights management strategy for the much-needed conceptual shift among water professionals. Supply-side story being finite, demand-side story is becoming increasingly disturbing. Demand for water in many parts of the world is much in excess of the availability. The traditional method of structural interventions and water supplies is proving inadequate to meet the current needs, much less the emerging demands. Attempts are being made to evolve systems that will sustain the natural ecosystems, while making water available for human requirements. Bandyopadhyay suggests an approach for providing interdisciplinary knowledge - a confluence of disciplines - to govern water management. Bandyopadhyay is head of the Centre for Development and Environment Policy at iim, Kolkata. He holds a doctorate in engineering from iit, Kanpur. For the past 25 years, he has been devoted to the objective of generating transdisciplinary public interest knowledge on critical issues related to sustainable development and equity. In the first chapter, he deals with disciplinary diversity in the knowledge gaps that need to be attended to in water science and policy. The same is true of water systems research, and education and research in water engineering. Bandyopadhyay has outlined nine areas for research, like creation of deeper ecological understanding of the various parts of the hydrological cycle, ecological understanding of flood and drought events, economics and valuation of water systems, etc. Water offers a basis for rapid creation of value, like in agriculture. Thermal power plants, dilution of pollutants, etc, require enormous volumes of water. With the advancement of technology, our dependence on water has grown. Pushed by the need for food self-sufficiency and requirement of power, India has made large investments in irrigation and hydropower dams. With increasing requirement of water, conflicts over sharing are multiplying. During the past 100 years, engineering has dramatically enhanced water availability, but at what long-term cost? Until recently, performance of engineers had made water management almost an exclusive area for them. According to Bandyopadhyay, the growing understanding of the social and ecological dimensions of water development has expanded the domain of water systems management, which can no longer be kept as an exclusive domain of engineering. The second chapter highlights the need for an eco-hydrological perspective on extreme events - floods and droughts. This is necessary for generation of a more realistic picture of such processes, their categories, positive contributions, and potential for damage. Such research would help negate the view of floods as disaster to be controlled. Once the floods are seen in their ecological context, many ecosystem services provided by floods and their contribution to human beings and economies would become evident - transportation and deposition of silts, spreading of aquatic biodiversity, recharge of surface and groundwater sources in the floodplains and so on - thus providing a new framework for a cost-benefit analysis of flood management projects. The emerging role of economics in enlarging the framework for water management is the subject of the third chapter. This will help assess the role of water in economic development more realistically. Application of new interdisciplinary knowledge for the much-debated and delayed (perhaps, a blessing in disguise) river-link project in India has been discussed in the last chapter. A closer look from an interdisciplinary viewpoint leads Bandyopadhyay to question the economic viability, social acceptability and ecological sustainability of the project. An impression has been created in the minds of the common people, so says Bandyopadhyay, that river-link would solve the twin problems of floods in the higher rainfall areas and of water scarcity in the areas with less rainfall. The scientific credibility of such a claim is not yet established. With cogent reasoning, he pleads that the wisdom of going ahead with the proposal with the present knowledge base and research is seriously questionable.