The Eucharistic Prayer is the most central and distinctive form of Christian public prayer apart from the Lord's Prayer itself. It gradually evolved into fixed forms during the early Christian centuries, and the Eucharistic Prayer of Addai and Mari is almost certainly the oldest such prayer still in use. Gelston's study presents a critical edition of the medieval Syriac text of this ancient Eucharistic prayer. Accompanied by a critical apparatus and a translation, the book addresses such literary, critical, and historical questions as the parallels with the Maronite anaphora Sharar, and provides an opportunity to detect possible later accretions and modifications. A reconstruction of the Prayer as it may have been at the beginning of the fifth century is offered in an appendix.