This chapter shows that the logical foundations for the principles of group formation in two Subarctic Athapaskan societies, the Beaver and the Slavey, by a particular kind of social structure. It explores how critical aspects of this social structure in a kinship terminology whose formal properties have been explored for societies elsewhere in the world. The chapter demonstrates conclusively that this basic logic operates in concert with other group forming principles, such as residence and recruitment, so that different combinations of these factors can be shown to produce patterned socioeconomic variability among the Beaver and Slavey. There exists a consensus on the existence of a duality in social organization which partitions Arctic Drainage Athapaskan societies. The chapter concludes that “confusion” in the Lynx Point Slavey terminology arises from different interpretations of the same kin relationships applied by Lynx Point individuals.