Eusebius the Evangelist analyzes Eusebius of Caesarea's fourth-century reconfiguration of the Gospels as a window into broader questions of technology and textuality in the ancient Mediterranean. The four Gospels of the New Testament (Matthew, Mark, Luke, and John) share language, narratives, and ideas, yet they also differ in structure and detail. The sophisticated system through which Eusebius organized this intricate web of textual relationships is known as the Eusebian apparatus. Eusebius' editorial intervention-involving tables, sectioning, and tables of contents-participates in a broader late ancient transformation in reading and knowledge. To illuminate Eusebius' innovative use of textual technologies, the study juxtaposes diverse ancient disciplines-including chronography, astronomy, geography, medicine, philosophy, and textual criticism-with a wide range of early Christian sources, attending to neglected evidence from material texts and technical literature. These varied phenomena reveal how Eusebius' fourfold Gospel worked in the hands of readers. Eusebius' creative juxtapositions of Gospel material had an enduring impact on Gospel reading. Not only did Eusebius continue earlier trajectories of Gospel writing, but his apparatus continued to generate new possibilities in the hands of readers. For more than a millennium, in over a dozen languages and in thousands of manuscripts, Eusebius' invention transformed readers' encounters with Gospel text on the page. By employing emerging textual technologies, Eusebius created new possibilities of reading, thereby rewriting the fourfold Gospel in a significant and durable way.