Borders mark but also construct and (re-)produce spaces, conceptualised as being given in a homogenous and in the same time in an enclosed way. Beyond such concepts, which take borders in a narrow sense as territorially fixed and given phenomena, the papers in this SW&S.Special Issue try to decode borders as historical, social and cultural formats and processes. The premise of the following papers is therefore that borders – or boundaries - can't be defined 'out of themselves', but they should be understood in relation to their symbolical dimensions and the surrounding spaces, the included and excluded parts. Borders are in this sense conceptualised in a strict relational way and are not limited to a territorial meaning. Otherwise, if we draw or change borders, e.g. as a geographical line, we already (re) produce or question the imagined unity of a space, a scene or a sphere embraced by these borders.