This book maps the relationship between Matthew's Gospel and the Didache. No consensus regarding the nature of this relationship has yet been achieved; nor has serious consideration been given to the possibility that Matthew depended directly on the Didache. If it may be shown that this was in fact the case, then this infamously enigmatic text may finally be used to answer a series of tantalising questions: What is the pattern of the Synoptic relationships? How did the earliest Jewish Christians incorporate Gentiles? What was the shape of eucharistic worship in the first century? This is volume 254 in the Journal for the Study of the New Testament Supplement Series.