The results of investment in irrigation projects in developing countries have often been disappointing both to investors and to local beneficiaries. The editors argue that the ultimate goals of irrigation projects must be set within the larger context of general social issues. Economic efficiency must often be weighed against social gains; irrigation projects cannot be conceived simply as technical problems, and structures must be designed with reference to their continuing maintenance and operation. Using a management model, the contributors offer new perspectives on the evaluation of investment priorities and the potential benefits of irrigation projects in developing countries.