The political economies of the states of Southeast Europe after the Second World War were shaped by the doctrine of development. In the long term and from a global perspective, development politics failed to advance the global position of the states of the region and to undo inequality within the region. Notwithstanding these failures, the social and spatial dynamics generated by the doctrine of development are essential to explain some outstanding features of the region’s recent social history, including social conflict, polarisation, and migration. This project analyses the socio-spatial characteristics and impact of development politics after the Second World War from the perspective of the region’s inner peripheries. The project is conceived around a three-tier approach. It is based on micro-historical studies of social change in peripheral localities of Southeast Europe. The project focusses on structural processes of rural and regional development, urbanization, and industrialization in particular units of analysis such as cities, factories, and rural areas. It considers the interplay of politics of accelerated development, local patterns of weak statehood and socio-economic peripherality, and rooted social relations. At the meso level, the project scrutinises the structural commonalities between peripheral localities within Southeast Europe and situates these in the context of the imperial and post-imperial legacies shaping Southeast Europe as a historical region. Finally, the project enters into cross-regional dialogues to analyse the connections between development politics, sociospatial polarisation, and social dynamics at wider and global scales.