The book is an investigation into the material reception of the Shepherd of Hermas as a case study of early Christian literary authority. An idiosyncratic early Christian apocalyptic work, the Shepherd was broadly copied and used often alongside biblical texts not only in Greek, but also in Latin, Coptic, Ethiopic, Armenian, Georgian and, as authoritative even in non-Christian context, in Middle-Persian. Drawing on patristic sources, late antique book-lists, and several manuscript traditions, the book challenges long-held assumptions about the outlook of its earliest reception and about its fourth-century rejection. Rather than a narrative of decline, the book proposes a model of continuity and illuminates how the Shepherd was continuously used in theological, catechetical, and liturgical contexts across centuries, and maintained a consistent status as a scriptural secondary book—neither fully canonical nor discarded—throughout late antiquity.