Elizabeth J. B. Corsar addresses the perennial New Testament question of the relationship between the Gospel of John and the Synoptic Gospels, with particular attention to the Gospel of Mark. She identifies and illustrates the theory and practice of source reworking within ancient compositional culture and demonstrates that the author of John's Gospel operates in a manner broadly analogous to this literary convention, especially in his reworking of Mark for the composition of his own Gospel. The study begins with an introductory chapter that surveys the history of scholarly debate concerning the relationship between John and the Synoptic Gospels, tracing the development of positions ranging from assumptions of Johannine independence to arguments for various forms of literary dependence, with a particular focus on Mark. To situate the present argument within its broader literary context, in the main part of the study, Corsar engages with a representative selection of ancient literary theorists and authors broadly contemporaneous with the Johannine milieu in order to assess the dominant compositional expectations and practices. Furthermore, in order to demonstrate more concretely the author's use of such techniques of reworking, Corsar employs John 1-2 as a focused test case, comparing these chapters with parallel material in Mark's Gospel.