I have just finished reading a new book by Francis Watson entitled Gospel Writing: A Canonical Perspective. Dr. Watson is a professor in the Department of Theology and Religion at Durham University in England and has worked and written extensively in Gospel interpretation. This book is a foray into a new paradigm for understanding the Gospels which carefully considers the reception history of the Gospels: how and why Gospels were written and how the four-fold canonical Gospels were accepted as such. Dr. Watson describes the book himself on his Durham University profile page:
My move to Durham coincided with the start of a new project on early Christian gospels, both canonical and noncanonical, with a particular focus on the formation and significance of the four gospel collection. This has now resulted in a book entitled Gospel Writing: A Canonical Perspective (Eerdmans 2013, 655 pp), which brings historical, hermeneutical and theological perspectives to bear on the question what it means for a gospel to be “canonical” or "noncanonical". The book proposes a new and broader paradigm for the study of the gospels which includes their early reception not only in theological writing but also in art (see http://gospelwriting.wordpress.com/.)
In a nutshell, Watson argues that the identification of four Gospels as canonical is an interpretive construct, separate from the action of gospel writing itself. This does not mean that Watson denigrates, dissolves, or denies the canon. Far from it. Watson values the canon as a construct for interpreting the texts contained therein. What Watson argues is that the act of gospel writing itself took place before, during, and without regard to the process of canonical selection. This means that the individual theology and reception history of the Gospels can and should be studied profitably through a comparison between the canonical Gospels and those termed apocryphal.
A simple illustration about what Watson is trying to do will help clarify. In NT departments all over the world, the four Gospels are studied by comparing and contrasting them, elucidating them by showing how they are at the same time related and different. Matthew is compared to Mark is compared to Luke is compared to John, with various arrangements of dependence acknowledged and accepted. Now consider the Coptic Gospel of Thomas. In those same departments, Thomas is often excluded from consideration because of its dependent character, that is, it shows dependence upon the canonical Gospels. Here's the point: If we can accept that Matthew was dependent upon Mark, for example, and profitably understand the theology of each because of that dependence, why do we a priori exclude the Gospel of Thomas because of that same relationship of dependence? The answer is because of the canon. Thus the canonical construct becomes an interpretive key, but we cannot properly understand the value of that interpretive key until we examine both what was in it and excluded from it and the relationships between them.
Watson's tome touches a broad swath of NT disciplines, including but not limited to exegesis, theology, reception history, and history of interpretation. For that reason it is a challenging read. I can't say that I agree with everything he has written here, but there is food for thought everywhere and his central thesis merits careful consideration.