Desertification is defined as large-scale dryland degradation resulting from human activity or the advancement of arid deserts into surrounding regions. This global problem threatens over 250 million people living in dryland regions that cover approximately 35 million km2 in nearly 100 countries. Only recently has global climate change received increasing attention as a major factor that contributes to desertification. At the 1992 United Nations Conference on Environment and Development held in Rio de Janeiro, the effect of climate and drought on land degradation was extensively discussed. Interactions of Desertification and Climate is a direct outcome of this meeting and was written to provide a comprehensive report for understanding relations between climate, drought, and land degradation and desertification.