Deserts are parts of the Earth that receive little or no rain; 25 cm or less per year. The physical processes that act upon these parched lands are vastly different from those that shape the more humid parts of the terrestrial landmasses. In the desert, wind is a major agent of erosion and transportation. As the results of recent space missions have indicated, this is also true in the case of the planet Mars. Thus, our understanding of desert processes sheds light on fundamental planetary processes that may apply on any planetary body that is enveloped by a windy atmosphere. An understanding of the physical layout of arid lands, and the nature of processes that initiate changes therein is also fundamental to thoughtful utilization of these lands for the benefit of mankind. It is with this in mind that we prepared this book for publication. We believe that the collection of articles in this book will be useful to scientists who are interested in desert landforms and processes, and to planners of economic develop­ ment of arid lands. The book also serves as a guide for students as to the state of our knowledge in this field as well as to the topics that require additional research.