From the range of the five horizontally-covered research areas clearly defined, I also see these areas vertically combined with at least four layers among the complexity of their interweaving processes from the departure of demographic approaches on any particular theatre production. They are: a) the most external layer of anthropological behavioral features among various ethnic groups and their national, regional as well as religious communities; b) the layer of individual human performative distinctiveness inevitably destined and regulated by the social and political diversities, though, influenced by the increasingly-globalized world cultures; c) the layer of performance art, on which various visual and performing arts as well as any cultural and aesthetic deliberations mutually influence and integrate with each other; and d) finally, the kern of production demography with its layer of performing arts, on which each single stage production is empowered and negotiated with diversified literary, dramatic, dramaturgical and theatrical, and even technical and technological traditions and developments.  Therefore, these complex approaches of interweaving performance cultures accessed and examined both vertically and horizontally make theatre studies today the most significant and challenging subject beyond its original scope of meaning and definition.