After I finished reading Richard Elliott Friedman book entitled "Who Wrote The Bible?" I became a firm believer in the Documnentary Hypopthesis. I enjoyed the book so much I decided to read it a second time. After re-reading the book things no longer made sense. I started to notice a lot of contradictions and circular reasoning. I decided to purchase "The Bible With Sources Revealed" (also by Richard Elliott Friedman) to further investagte the matter and concluded that the Documentary Hypothesis is purely the result of Friedman's active imagination.
The most ridiculous part of the Documentary Hypothesis is the idea of a redactor. The redactor is used as a scapegoat to explain away many contradicitions, such a "Elohim" being used in the 'J' text (Gen 2-3). Friedman is basically saying anything that contradicts the Documentnay Hypothesis was added by a redactor which puts it in the 'R' class, which means it's farther proof of the Documentnary Hypothesis. Warped logic at it's finest.
Furthermore, the vast majority of "scholars" no longer subscribe to the Documetnary Hypothesis as it has been debunked plenty of times. Most notably by Umberto Cassuto in his book "The Documentary Hypothesis And The Composition Of The Pentateuch" ( http://www.amazon.com/Documentary-Hypothesis-Umberto-Cassuto/dp/9657052351/ref=pd_bxgy_b_img_b ) and Norman R. Whybray in "The Making Of The Pentateuch" ( http://www.amazon.com/Making-Pentateuch-Methodological-Library-Testament/dp/1850750637 ) . For those however who can't/won't purchase these books, this ( http://www.biblearchaeology.org/post/2010/09/24/the-documentary-hypothesis.aspx ) site gives a summary of all the things wrong with the Documentary Hypothesis.