Book excerpt: Innovations and Challenges in Grammar traces the history of common understandings of what grammar is and where it came from to demonstrate how ‘rules’ are anything but fixed and immutable. In doing so, it deconstructs the notion of ‘correctness’ to show how grammar changes over time thereby exposing the social and historical forces that mould and change usage. The questions that this book grapples with are: Can we separate grammar from the other features of the language system and get a handle on it as an independent entity? Why should there be strikingly different notions and models of grammar? Are they (in)compatible? Which one or ones fit(s) best the needs of applied linguists if we assume that applied linguists address real-world problems through the lens of language? And which one(s) could make most sense to non-specialists? If grammar is not a fixed entity but a set of usage norms in constant flux, how can we persuade other professionals and the general public that this is a positive observation rather than a threat to civilised behaviour? This book draws upon both historical and modern grammars from across the globe to provide a multi-layered picture of world grammar. It will be useful to teachers and researchers of English as a first and second language, though the inclusion of examples from and occasional references to other languages (French, Spanish, Malay, Swedish, Russian, Welsh, Burmese, Japanese) is intended to broaden the appeal to teachers and researchers of other languages. It will be of use to final-year undergraduate, postgraduate and doctoral students as well as secondary and tertiary level teachers and researchers in applied linguistics, second language acquisition and grammar pedagogy.