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Proceedings of an international research and development conference, Tuscon, Arizona, October 1985. One hundred and twenty-eight papers are presented in this hefty volume. They are grouped into chapters covering climate, underutilized plants, irrigation and water management, biosphere reserves, water policy, animal resources, desert ecology, crop physiology and agronomy, urban environments, desertification, land intensification, and other topics related to the economy and management of arid lands. Provides detailed treatment of topics in traditional logic: theory of terms, theory of definition, informal fallacies, and division and classification.