First published in 1951, this book forms a critique of the Two-Source Hypothesis, the theory in biblical studies that postulates the existence of a lost 'Q' Gospel. The Q theory achieved popularity through its formal completeness in explaining the presence of parallel verses in Luke and Matthew with no parallel in Mark. Yet, as Butler argues in this book, these narrative links can also be explained by a direct comparison of the third and fourth Gospels, one that avoids the necessity of a missing source. The text is highly detailed and contains numerous references to original material, together with generous additional notes. It will be of value to anyone with an interest in biblical history and theology.