This chapter outlines the theoretical fundamentals of the legal segmentation approach and sketches the logics of its historical development in the Global South (GS) and North (GN). Aiming to make historical forms of social injustice traceable, it elaborates central notions for the analysis of legal and normative segmentation including legal and normative pluralism. Furthermore, the influence of different social policy fields and actors on the emergence and evolution of patterns of segmentation is outlined. Successive phases and layers of institutionalising legal segmentation are distinguished: In the North, the influence of internalising the ‘spirit of capitalism’ inculcated by segmenting legislation is analysed, highlighting the standard employment relationship. In contrast, utilitarianist, consequential approaches of forming normative frameworks for the exploitation of workers building upon colonial pasts are discussed for the GS.