Scientific specialists have found that they cannot achieve a mastery in a narrow field without understanding better the neighbouring disciplines, the whole system that constitues a desert environment: authorities such as governmental officials who have broad responsibilities for desertic regions have found that they need more specific information about the nature and the future of arid lands.The first of a continuing number of publications to be compiled under the leadership ofthe Advisory Committee for Arid Lands Research of the University of Arizona, and theCommittee on Arid Lands of the American Association for the Advancement of Science.