The manuscript copies of Chaucer’s works preserve valuable information concerning Chaucer’s linguistic practices and the ways in which scribes responded to these. This book draws on recent developments in Middle English dialectology, textual criticism and the application of computers to manuscript studies to assess the evidence Chaucerian manuscripts provide for reconstructing Chaucer’s own language and his linguistic environment. This book considers how scribes, editors and Chaucerian poets transmitted and updated Chaucer’s language and the implications of this for our understanding of Chaucerian book production and reception, and the processes of linguistic change in the fifteenth century. SIMON HOROBIN lectures on English language at the University of Glasgow.