There is increasing pressure worldwide on available water resources. These pressures arise from a number of factors, including growing populations, increased wealth and urbanization, increased industrialization, and demands from society and environmental groups for safe-guards to protect water resources and the aquatic environment. In many locations climate change is adding to these pressures. In many countries irrigated agriculture consumes a large proportion of the available water resources, often over 70% of the total. There is considerable pressure to release water for other uses, and as a sector, irrigated agriculture will have to increase its efficiency and productivity of water use. A new era is dawning for water management in the irrigated agriculture sec-tor, where the management effort and returns to management are required, recognized and rewarded. This book draws on the authors experience and work over many years and in many countries in the management, operation and maintenance of irrigation and drainage schemes. The book provides knowledge for management of irrigation and drainage systems in the 21st century, covering the traditional technical areas related to system operation and maintenance and expanding managerial, institutional and organizational aspects related to the changing political, social and economic environment.