The Shepherd of Hermas (70-150 CE) is one of the oldest Christian works from a major urban center. While the majority of manuscript evidence of the Shepherd is concentrated in North Africa, the work has long-standing association with the city of Rome. It consists of three major sections: the Book of Visions, the Mandates, and the Similitudes. The Shepherd was enormously popular during the early centuries as a catechetical text used for moral formation. Its manuscript evidence during the early centuries far exceeded that of the Gospels. This book uses cognitive literary theory, specifically the approach known as enactive reading, to investigate why a work that was exceedingly popular among elite readers in antiquity has failed to receive the same reception by modern scholars. The study focuses on the first section of the Shepherd known as the Book of Visions, which narrates Hermas's visionary experiences in first-person voice. The book argues that enactive reading can help to generate immersive experiences of Hermas's visions and explain the success and appeal of the Book of Visions among ancient readers. Cognitive approaches also highlight how modern scholars trained to read apocalypses 'against the grain' to search for historical or theological information fail to notice and appreciate the very things that made apocalypses engaging and entertaining to a broad range of ancient readers and hearers.