This book is the first English translation of a text that Michael Cahill identifies as the first formal commentary on Mark's Gospel. Thought to have been written by an early seventh-century abbot, the commentary was for almost 1000 years attributed to St. Jerome and as such exercised incalculable influence on subsequent commentary. St. Thomas Aquinas drew on it freely in his Catena Aurea, for example, as did the highly influential Counter-Reformation commentary of Cornelius a Lapide. Renaissance scholarship demoted the work to the pseudepigrapha of Jerome and it clearly lost status as a result. However, the contemporary recovery of interest in the commentary tradition ensures a welcome for the publication of this translation. Irrespective of authorship, the text is important in the history of biblical interpretation--it is the first commentary on Mark, and has had wide influence in the Latin west. It is written in the allegorical style, and attempts to provide an application of the gospel text to the practice of Christian discipleship. It is characterized by the use of other biblical texts, and through the use of bold face and italics in the translation, the reader is able to see the extent of quotation, paraphrase, and allusion. The extensive notes are designed to provide information on source material and on the author's technique. As the first Markan commentary this text holds a unique place in the history of biblical exegesis. This translation will make it available to scholars who do not read Latin, and will serve as a useful introduction to early and medieval Bible commentary, both in format and content.