I've finished the next chapter in Terence Donaldson's Jews and Anti-Judaism in the New Testament. It is on the Gospel of John and may be my post tomorrow. But I was struck by the gap between the church and the academy when I read Donaldson's description of the current consensus on the "two-level" nature of John's Gospel. I'm struck because I have to imagine that the vast majority of pastors in America, after reading this post, would say, "Consensus? I've never even heard of that." Or even more: "I completely disagree with that" or "That doesn't fit with the way I approach Scripture."
It is a microcosm of many issues, where the vast majority of experts in a particular subject who follow the standards of "objective" research have come to a particular perspective that is highly questioned on a popular level. Then usually a counter-community of experts arises with a primary goal of arguing that the evidence can be read in a different way. Such counter-guilds appear to be following the rules of research but they do so from a deductive rather than inductive perspective. They start with their conclusion and go to the evidence to support it rather than starting with the evidence and drawing conclusions that seem to fit the data most straightforwardly. [1 postmodern footnote]
Enough preface. And now, the "consensus" of experts on the history of the Gospel of John, forged primarily by Raymond Brown, a godly Roman Catholic who passed away a couple years ago. The consensus is that John has two interpretive layers. The one has to do with Jesus. The other has to do with the individuals who produced John and their "community."
1. The Gospel of John has some seams...
... that seem to indicate that it was not written in one sitting. Rather, it seems to have developed as a document over time. In 3:22 Jesus comes into Judea... but he has already been there since 2:13. In 6:1 Jesus goes to the other side of Galilee... but he was not on this side before but in Jerusalem. In 14:31 Jesus tells his disciples to get up... but he talks for three more chapters before they do. Chapter 20 ends the book... but then it goes on and tells about the author of John in the third person in chapter 21. One that Donaldson doesn't mention is the fact that Jesus performs many signs (2:23; 3:2) in between his first (2:11) and second (4:54) signs.
It thus seems quite likely that the Gospel of John was written in stages and, since the last chapter talks about the beloved disciple as author, it would seem that John himself (remembering that we don't actually know it was John--the text never identifies the beloved disciple) was not the one who put it into its current form.
As an inspiration break, I don't see any of this as contradicting the idea of inspiration. Editing can be inspired just as well as sitting down and writing. It might, however, mess with unexamined assumptions we have.
2. The Beloved Disciple
The majority of John experts do not think that this was John the son of Zebedee but another follower of Jesus who was not one of the Twelve (Hengel suggested someone we know of called John the elder). The Twelve do not play a major role in John and in fact Peter is subordinated to the beloved disciple in the narrative. Given the prominence of Judea and Jerusalem in John, the majority consider this disciple to be from Judea rather than Galilee.
To some, the extra interest in John the Baptist suggests the author might have started as a follower of him. At the same time, I would add, John de-emphasized the Baptist in a way that may say something about the situation at Ephesus and followers of JB even later when Paul was there (cf. Acts 19).
3. Expulsion from synagogue
The Gospel of John is quite distinct from the Synoptics in its theology. It is, for example, far more dualistic. Its Christology is more explicitly "high" than most of the rest of the New Testament. In Brown's hypothesis (supplemented by J. Louis Martyn), John's group is eventually expelled from the Jewish synagogue. In the majority hypothesis, it is unlikely at the time of Jesus that anyone would be expelled from a synagogue for believing Jesus was the Messiah. The incidents with the blind man and his parents in John would thus reflect the situation of the community that produced the Gospel rather than incidents from the historical Jesus.
4. Arrival in Ephesus
Tradition has John at Ephesus, and the majority hypothesis is comfortable with the idea that John and his community might have left Judea around the time of the Jewish War and moved to Ephesus.
5. John reaches its current form.
After John's death, John 21 was added as an epilog, while additional material like chapters 15-17 was added.
Something like the preceding is the majority hypothesis. Certainly it is subject to critique and evaluation. Some parts seem more solid to me than others. For example, that the Gospel of John developed in stages seems very likely to me because of the seams. It also seems likely to me that it reached its current form after the death of the Beloved Disciple. I am also very sympathetic to the idea that this disciple was not one of the Twelve, that he was from Judea, and that he died in Ephesus.
The two level reading of John is what I suspect may be the most controversial in pulpit and pew. It implies that John is not straightforward history but is highly symbolic and a mixture of two histories--that of Jesus and that of one group of early believers. I might mention that Richard Bauckham has recently questioned whether any of the gospels can be read as written for an individual community.
I thought you'd want to know ;-)
 No one is objective. The theories of inductive research are always subject to critique and revision. They often are at some point.