This master thesis is divided into two main parts. The first section focus deals with the physical geographical aspects of deserts. The distinction to other landscapes is of particular relevance, whereas the lack of precipitation is used to distinct and classify arid areas. The global distribution of desert areas spans across two zones: the tropical/subtropical dry areas and the dry mid-latitudes. Different atmospheric processes are responsible for the formation and the continuity of deserts in these parts of the world. Desert areas can be classified according to either their continental position, or their ground level structure. Landscape formation processes, such as wind, erosion and weathering, play an important role in deserts and contribute to the formation and transformation of landscape forms in arid areas. The first part of this thesis ends with an insight into the plants and animals of these areas. The second section deals with interactions between man and the natural environment of deserts, whereas the mutual influence is emphasized. Oasis economy and nomadism are traditional economic systems, which are adapted to the natural environment of desert regions and represent a sustainable use of natural resources. Because of different processes, these economic systems have changed since the second half of the 20th century. Another form of interaction is desertification. This man-made expansion of deserts is caused by unadjusted interventions into the natural environment and overexploitation, inducing enormous problems on the edges of arid areas. In the context of desertification processes, the anthropogenic climate change plays a crucial role. Combating desertification globally is one of the big challenges of the 21st century and discussed in the last chapter of this master thesis.