The anaphora (eucharistic prayer) attributed to St John Chrysostom represents an important witness to the lex orandi of late antiquity. Still in use today in the Orthodox churches, as well as Byzantine-Rite Catholic and some Protestant churches, this anaphora is noteworthy for a variety of its features, including an institutional narrative without the iteration command, the precedence it gives to the commemorations/intercessions of the departed before those for the living, the offering of the eucharist for the saints/deceased including the Theotokos, as well as the pseudo-epigraphic attribution of the prayer to the 'golden-mouthed father'. For these reasons and more, this eucharistic prayer represents an extremely interesting case study. This book addresses questions related to the origins, alleged authorship, and evolution of the Chrysostom anaphora over the course of nearly a millennium. It investigates these issues through an original method that is focused on the continuous dialectic between the text and the contexts where this anaphora was copied and used. The author makes use of innovative digital resources and over 400 manuscripts produced between the eighth and seventeenth centuries, most of which are unedited, and opens up new horizons for the study of Christian prayer.