The many billions of dollars invested in canal irrigation in recent decades have had disappointing results. Rarely have projected benefits in well-being or production been achieved. In consequence, in the mid-1980s, further vast sums are being spent throughout the Third World on programmes for rehabilitation, canal lining, on farm development, and farmers' organisation. In this book, Robert Chambers shows that much of this policy and practice is based on misleading research and misdiagnosis. When applied to the complexity and uniqueness of canal irrigation systems, the normal professionalism of civil and agricultural engineers, agronomists, economists, and sociologists, leaves gaps which are keys to better performance. In successive chapters, five such gaps are analysed and presented: main system management, including the scheduling and delivery of water, and communications; canal irrigation at night; management of canal systems jointly by farmers and officials; professional conditions