The Social Atlas of Leipzig is the first atlas considering the social and urban ecological structural change in a big East German city. The main objectives are spatial registration, cartographic representation and assessment of these social consequences that accompany the abrupt transition from the centrally managed economy in the former GDR to the free market economy. Thus the social-spatial differentiation has to be investigated by means of selected social, political and economic factors including the actual land use, as well as structural, infrastructural and environmental characteristics. In consequence urban areas where gentrification or filtering down processes with concentration of poorness can be identified. The atlas consists of a textual part and a cartographic part. The textual part is divided in: (1.) description of objectives, structure and methodology of the social atlas (2.) discussion of roots and symptoms of segregation tendencies in East German cities (3.) characterization of nine types of social spaces inside the City of Leipzig (4.) analysis and evaluation of initial stages of social_spatial differentiation in Leipzig by means of interpreting several maps. // The cartographic part includes 49 maps: 23 maps describe the socio_demographic structure, 15 maps the residential structure, 6 maps the social infrastructure, 3 maps the land use and I map the types of social spaces. The atlas serves as a scientific basis to find out both common features and differences in the development of several urban areas, exemplary for the City of Leipzig. But the methodology can be used also from other cities. It has been created for a broad audience _ for urban and regional planners, investors, different authorities, scientists dealing with urban development and, last but not least, for the residents.