This book is a study of Chaucer's words. It describes how these words became evidence for calling Chaucer the "father of English poetry" but, also, why that label is wrong. It shows that Chaucer's language is, in fact, traditional and argues that his linguistic innovation was as much performance as fact. It provides a thorough history of every one of Chaucer's words and maps the origins and patterns of use that have made these words so compelling for six hundred years.