More than fifteen sites of either confirmed or conjectured urban status existed between the 6th and 19th centuries in the particular region of northeastern Mesopotamia, bounded by the rivers Great Zāb, Little Zāb and Tigris. This present study concentrates on the investigation of this urban network. The archaeological substance of the deserted sites is mostly very well preserved in the relief of the arid steppe environment and can be excellently identified in satellite images of several types. The archaeological investigation of these settlements, augmented by a revised historical topography, offers a unique opportunity for the holistic study of the diversity, temporal dynamics and mutual relationships within the urban network that developed in the hinterland of Baghdad and Samarra, the two largest super-centres of the Old World. This collective monograph puts together archaeological and historical data available for the individual sites, including analyses of pottery obtained by surface survey. The materially rich final report of the three-year project is supplemented by an interpretative chapter that focuses on detailed topographical comparisons of the sites, their landscape contexts, and the dynamics of the urban system within the framework of studies on Near-Eastern Islamic-period cities.