Whilst the city centre has been the focus of many research studies in recent decades, the urban periphery has received less detailed attention. Here, beyond the formally planned built up area, and often outside municipal limits, development has often been more haphazard, and in developing world cities, has often included illegal developments lacking in service infrastructure. This special edition looks at multiple aspects of the urban periphery: the large housing estates, the poverty of service infrastructure, the shanty developments, the industrial zones, the role of plans and policies, and the potential of the new technologies to address the resultant socio-economic malaise that often pervades parts of the urban periphery.