This book presents a comprehensive description of the hydrogeology and hydrologic processes at work in arid lands. It describes the techniques that can be used to assess and manage the water resources of these areas with an emphasis on groundwater resources, including recent advances in hydrologic evaluation and the differences between how aquifer systems behave in arid lands versus more humid areas. Also, changing climatic conditions will force water management systems to be more robust so that future water supply demands can be met as droughts become more intense and rainfall events become more intense.