This intellectual history of the disciplinary roots of second language (L2) writing research and pedagogy in English examines the influences of its feeder disciplines, composition studies and applied linguistics, and their parent disciplines, rhetoric and linguistics. After a brief history of L2 writing's two grandparent disciplines (rhetoric and linguistics) and its two parent disciplines (composition studies and applied linguistics), the article focuses on the effect of the two parent disciplines' conflicting identities. Whereas L2 writing benefits from its invigorating position at the confluence of these two intellectual streams, it has also been pulled in different incompatible directions resulting from differences, and even similarities, between applied linguistics' and composition studies' inquiry paradigms and traditions, their intellectual identities, and the material disciplinary manifestations of their organizations, conferences, and publications. A brief history of L2 writing pedagogy and research demonstrates the push and pull of the conflicting influences of its feeder disciplines.