This book explores the Matthean Posteriority Hypothesis (MPH), a largely neglected solution to the Synoptic Problem which holds that the author of the Gospel of Luke used the Gospel of Mark as a source, and that the author of the Gospel of Matthew used both the Gospel of Mark and the Gospel of Luke as sources. MacEwen begins with a survey of the scholars who have defended various forms of the MPH. Chapter 2 discusses two key lines of evidence which support the MPH. The first line of evidence is textual - demonstrating that Matthew could have known the contents of Luke's Gospel beyond merely the double tradition material. The second line of evidence, involving a study of strings of verbatim agreements in the Gospels, supports the view that Matthew depended directly on Luke. Chapter 3 explores evidence and arguments which can be seen as problematic for the MPH. MacEwen concludes that the MPH has been neither definitely proved nor disproved, and deserves further scholarly scrutiny.