"Grammatica," "Gramadach," and "Gramadeg": "Vernacular grammar and grammarians in medieval Ireland and Wales" is concerned with the history of linguistic ideas and literary theory in the vernacular languages of medieval Ireland and Wales. While much good work, especially by Vivian Law, has been done on the Latin materials, this volume is the first to engage with the vernacular texts. It consists of ten essays that explore a range of interconnected topics relating to these themes. Yet while the contributors offer a close analysis of the development of linguistic thought in these literary traditions, they likewise seek to situate their discussions within the wider context of European grammatical learning during this period, considering both the widespread influence of texts from classical linguistic tradition and also the significance of sources from other contemporary learned disciplines for our understanding of the history of linguistics in the medieval world.