The traditional bipolar approach to literature and to its consumers continues to dominate Arab thought and scholarship, as reflected, for example, by Arab views concerning the relationship between two of the most important poles of the literary system, canonical and non-canonical literatures. In fact, despite the rise of non-canonical literatures, in particular popular literature, after World War II, Arab scholarship has refused so far to give up its polarized view of the interrelation between the two. By polarized I mean the view that canonical and non-canonical literatures are conflicting and mutually incompatible, that they can be clearly and unequivocally distinguished and would never be confused with each other. In the present study, I wish to shed some light on the relations between various aspects of a single literary system, to demonstrate the importance of recognizing the existence of non-canonical literatures, and to inquire into the latter's function as contributing to the overall stability of a literary system. To do this, I will utilize Even-Zohar's theory of literary systems and their evolution, which I will apply to Arabic language and literature and use to develop a novel, more objective approach to non-canonical literature than the traditional view, a view that considers this kind of literature a threat to the very existence of fushā writing and canonical literature. I will follow this with a terminological analysis of two distinct branches of non-canonical literature, viz. vernacular literature and popular literature, each of which I will attempt to delineate and to distinguish from the other.