UNESCO has studied extensively the problem of arid zones, which cover almost a third of the earths surface. This film descrives the activities of the Beni Abès Scientific Research Center, set up by the French government in the Sahara. Illustration of the successes of the center, and demonstrates the need for international cooperation in the fight against desertification. Footage: Saharan life, fauna, flora, rites, customs, populations. Desert images.