Speculum vitae is the hitherto unedited translation into Middle English verse of Lorens of Orleans's profoundly influential pastoral treatise, Somme le roi. The translation, in Yorkshire dialect, is a vast work, 16,000 lines in four-stress couplets, and more than forty extant copies testify to its popularity. Despite the evident editorial difficulties which it presents, the previous neglect of Speculum vitae is to be regretted. It is the product of an important regional centre, and should take its place alongside the other monuments of this tradition: Cursor Mundi, The Prick of Conscience, and the Northern Homily Cycle. Moreover, it is important as a versification of Lorens's catechetical classic, which was a ceaseless inspriation for Middle English prose translators - the Speculum is the only known verse translation. This edition is based on a collation of the five early manuscripts, all Yorkshire productions, which communicate a distinct, and usually more satisfactory, form of the text than the remaining copies. The Introduction will discuss the manuscripts, authorship, dialect, and date, with an account both of its source and other works which it has influenced. The volume will contain a bibliography, notes, and glossary.