The Rhaeto-Romance languages have been known as such to the linguistic community since the pioneering studies of Ascoli and Gartner over a century ago. There has never been a community of Rhaeto-Romance speakers with a common history or polity and the dialects are mutually unintelligible, but a unity, based on a number of common features has been advanced. In what sense can Rhaeto-Romance be seen as a single entity and to what extent is it the creation of a small number of academic visionaries? This book, the first general description of the Rhaeto-Romance languages to be written in English, provides a critical examination of the phonology, morphology, lexicon, and syntax of the modern RR dialects within the broader perspective of Romance comparative linguistics.