The relationship between twentieth-century literary criticism and linguistics has never been a particularly comfortable one. The sense of unease is most pronounced in the literary-critical world, fuelled mainly by a reluctance to submit the mysteries and rarefications of an art form to the mechanical indifference of a science, but the relationship is sustained by a simple and undeniable fact: literature is the only art form whose raw material is drawn exclusively from language. Literary linguists have given roughly equal attention to prose fiction and to poetry, but the latter has a prior claim to the methodologies and perspectives offered by modern linguistics because, as Jakobson argues, the structural properties of poetic language are also, to a large extent, its subject. The meeting-point for the formal and the referential axes of poetry is versification, and Jakobson’s investigations of this confluence form the core of his theory of poetry.