JEDP, I knew you well.
There is scholarship in different circles that tries to discredit the Torah (or first 5 books of the Bible—specifically Genesis) by stating that it was complied by 4 authors—none of which was Moses.
Tackling this head on—there is no problem with a different writer for Genesis. Clearly, it’s not a problem for Moses to have edited documents that he had on hand1 that we do not have access to.
Furthermore, there’s a passage at the end of Deuteronomy that could not have been written by Moses, because it records his death.
Neither of these present a problem for the Bible or its veracity. Since the Bible is a conglomeration of different authors, the question does not lie in “who wrote this” but “what was written.”
To fully talk and critique the Documentary Hypothesis would take more space than time allows. For those that are interested, I suggest that you purchase or borrow The New Evidence That Demands A Verdict Fully Updated To Answer The Questions Challenging Christians Today. This book is full of great facts about the Bible—both Old and New Testament—and goes into great detail about JEDP and the Documentary Hypothesis.
- At that time, Moses may have had documents created by Adam himself, brought over on the ark. Some scholars believe that some of the verses would indicate different authorship, much like journaling or blogging today. If that is the case, we may be reading what Adam and his descendents wrote that has been long lost to time in other places!