The Book of J was one of those things that I just stumbled over (in this case, at the Newberry Library Book Fair ... a hardcover signed copy for two bucks!) and decided to pick up, and then for no particular reason opted to slot it into my reading schedule (it was "something different" from what I'd been reading, so was somewhat functioning as "mental floss"). It's sort of an odd book ... it's "interpreted by" Harold Bloom based on the translation of David Rosenberg ... but is essentially a book of Biblical exegesis, looking at the "J" author of substantial bits of the Old Testament. Now, as a former Religion Major, I am at least conversant with the analytical dissection of various ancient texts, but was not specifically up to speed on this particular area. It seems that "J" is the extracted source of many of the classic Bible stories, as opposed to "E", "P", "D", or "R" who were other writers/schools that either added materials, edited out materials, re-organized materials, or otherwise spun a collection of bronze-age tribal myths into the document which has inexplicably held sway over vast chunks of humanity over the past couple of millennia.
Bloom (whose own writing in remarkably well crafted, I found myself marveling over many phrases and wondering just how long it took him to come up with such stellar prose!), posits that "J" was writing in the court of Solomon, perhaps in the days of Rehoboam, and that (from various thematic clues) she was a noble lady of the court. Bloom compares her to Shakespeare, Chaucer, and even to later authors such as Kafka, pointing to the ironic stance emblematic to the "J" material. The God of the "J" material is hardly the deity envisioned by most Christians or Muslims (or for that matter, most Jews), as He is a being who eats, rests, walks, and argues with His chosen creations. This God also appears to manifest behaviors that would be, in a human, regarded and psychologically unstable ... but these "quirks" are simply noted, ironically, and not questioned in the "J" material.
The book is basically in three parts, the first section where Bloom puts forth his reasoning about "J" and provides more info on the times and the location, a central section which is Rosenberg's (who, I take it, seems to be a noted Hebrew poet) translation of the extracted "J" material, and a final section where Bloom walks us through the story, highlighting major characters. This is fairly interesting stuff (especially for Biblical exegesis), and, as I noted previously, quite well written.
The Book of J appears to still be in print in a paperback edition, so should be reasonably easy to find if you were so inclined. However, you can pick up a "like new" copy from the Amazon new/used vendors for as little as a penny, so there is that as an alternative. Again, I don't know how interested "most folks" would be in this volume ... but if picking apart a puzzle based on ancient texts is your thing, this would probably work for you.

