Human-induced salinisation is a major threat to the world's land and water resources. Inadequate development of irrigation projects, inefficient irrigation, lack of proper drainage, and environmental mismanagement such as the clearing of native vegetation, are responsible for the loss of millions of hectares of agricultural and grazing land, as well as the misuse of scarce water resources. The first part of this book analyses the problem in the context of the world's population, its climate and its land and water resources. It reviews irrigation methods and crop water requirements, the processes of salinisation, and its management. The second part describes irrigated land, dryland and water-resource salinity problems in 11 countries, which contain approximately 70 per cent of the world's irrigated land. In each case study, background data, environmental conditions and past management practices are given to provide an understanding of why salinity occurs in particular places, and of the management methods employed against it.