Cross-border twin cities have a particular spatial organization in the sense that geographic proximity is an intermingling factor of urban areas and economic interdependence allowing a transnational development. Their transnational setting, i.e. through a border, covers a multiscalar approach on a provincial scale (within a State) on the one hand, and a regional scale on the other, combining at least two States. This kind of urban layout therefore leads to a spatial reorganization networking a new regional territory which responds to the economic guidelines of partner States (Raffestin 1974; Taillard 2010). Infrastructure networking, administrative harmonization, respective comparative advantages and complementarities have made these urban areas a layout that may support an economic dynamism specific to transnational regions (Maneepong et al. 2004; Taillard 2010; Goldblum et al. 2007). The border is thus no longer exclusively a component of separation, but may also turn into a spatial bridge between two bordered provinces (Arnold 2010).

Among the twin towns bordering Thailand and Malaysia, the Danok- Bukit Kayu Hitam pair may have the greatest potential to be developed into a major growth area. Although the urban and economic layouts fall into the category of a twin city, it has not however been officially stated by the Malaysian and Thai governments so far. It is thus by no means as institutionalized as those at the southern boundary of China, which are discussed in more detail by Sébastien Colin in this book. This study aims to investigate how the twin cities of Danok and Bukit Kayu Hitam may become a peripheral growth centre for both Thailand and Malaysia, thus promoting sustainable development in the region.

This study is organized according to approaches on different scales (see Map 13.1) The following section will provide a local scale by studying the district location and socio-economic backgrounds of Sadao and Kubang Pasu and the twin cities in question. The second part will cover a comparative analysis of the twin cities to determine whether their status may imply identical dynamics; we shall also touch on the institutional framework of the aforementioned cities.