Medieval commentaries typically included an accessus, a standardized introduction to an author or book. In the twelfth century these introductions were anthologised, referred to now as Accessus ad auctores. They served as the first handbooks of literary criticism. The earliest and most comprehensive example, Bayerische Staatsbibliothek, Clm 19475, saec. XII,is presented here for the first time in a faithful critical edition, with a new translation and explanatory notes addressing different aspects of the text. This book's aim is to present an accurate version of the text while respecting the arrangement and integrity of the anthology as a whole, and includes previously unpublished material from the anthology.