This book presents a comprehensive portrait of the Kitāb Sībawayhi. It offers new insights into its historical and linguistic arguments and underlines their strong correlation. The decisive historical argument highlights al-Ḥīra’s role, not only as the centre of pre-Islamic Arabic culture, but also as the matrix within which early Arab linguistics grew and developed. The Kitāb’s value as a communicative grammar forms the crux of the linguistic argument. The complementarity of syntax and pragmatics is established as a condition sine qua non for Sībawayhi’s analysis of language. The benefits of a complementary approach are reflected in the analysis of nominal sentences and related notions of ibtidā’ and definiteness. The pragmatic principle of identifiability is uncovered as the ultimate determiner of word order.