Water is essential for a wide range of human activities and it exists in relatively finite amounts. When dealing with water management, different issues should be combined: water demand, water quality, irrigation and food production, ecosystem preservation, cost minimization, technological options, legislative frameworks, social impact. The main goal of the book is to give a general framework about Integrated Water Management (IWM), that is the planning and management of water resources integrating the different issues involved (ecological, economic, technical legislative, transboundary, etc.). The manuscript is the result of the research activity and the exchange of knowledge among a team of experts in different disciplines and institutions related to water resources, and includes both the different environmental problems that affect the very different ecosystems, and the main methodologies able to face the problem of IWM. The book is divided in three parts: Concepts and approaches of IWM (Part I), Case studies (Part II), and Reports of the working groups (Part III). Finally, the book contains a section of conclusions that includes discussion about the presented methodologies, approaches, and issues. In particular, the perspective of experts in different disciplines (engineering perspective, biology perspective, economic perspective, etc. has been given).