The Poema de mio Cid is in all respects a major text of early Spanish literature and an epic of great power. Its origins and authorship have long been a subject of dispute among scholars and this book, firmly based on rigorous research, proposes the view that the Poema was a wholly new work of the early thirteenth century written by a single author, Per Abad. The author argues that it was the first epic to be composed in Castilian and he examines the sources that the poet used for the structure of his work, for his rhetoric and for his metrical system. Throughout the work Professor Smith seeks not only to combat the competing 'traditionalist' and 'oralist' viewpoints, but also to give as clear a picture as possible of the cultural background in which the Poema was written and to enhance the standing of a remarkable poet.