December's recommendation: the Old Testament.
I began the "folklore recommendations" this year with Beowulf, remarking in passing that it is where every good old-fashioned English class begins. I didn't mean at the time for that comment to be prophetic, but in fact there has been a unifying logic behind my choices this year; I've selected works which have been foundational in English literature. I could have chosen Shakespeare for the end of the year (after all, I covered Chaucer in August), but his complete works seem rather much to tackle in a single month's recommendation, and I couldn't pick out a representational subset that satisfied me. So, instead -- and in honor of the season, though technically I've picked the wrong one -- I'm going to discuss the Old Testament.
This is, generally speaking, the text that is shared by Judaism and various forms of Christianity. The former refers to it as the Tanakh (the Torah being only the first five books), and not all denominations agree on which books to include, how to organize them, and what order to put them in. Wikipedia has a good overview of the different versions, if you're interested in comparing. If you weren't aware -- and you might not be; it's remarkable, what assumptions people have about the Bible that are quite wrong -- the Old Testament is not about Jesus, except insofar as some of the prophecies in it are about him, depending on who you ask. That's what the New Testament is for, and that's where Christianity and Judaism part ways.
But I'm not here to discuss theology; I'm here to discuss how the Old Testament might be interesting to you as a writer.
I'm somewhat shamed to admit that, despite my best intentions, I did not manage to read the entirety of the Old Testament before writing this recommendation. Let that be my first statement on its uses for writers: watch out, it's long. REALLY long. Even if you skip the bits about who begat whom, how to decorate a Jewish temple, and what God wants you to do about mildew. (Think I'm kidding about that last one? Go read Leviticus.) Since there was never a chance of me discussing all the books of the Old Testament individually, my failure doesn't prevent me from writing this recommendation anyway, but I thought I should be honest.
Back on the topic of what's in the text, though, aside from the evils of mildew and how to get rid of them in a righteous and God-fearing manner, there are some thumping good stories in the Old Testament. Sodom and Gomorrah get annihilated in Genesis. Moses does his whole Red Sea schtick in Exodus. Leviticus . . . let's just skip that one. Numbers is a bit better, though it too contains a lot of Judaic law, plus a lot of counting of people. (Where did you think the name came from?) Somewhat likewise with Deuteronomy. That's the Torah; the next segment is called the Nevi'im or Prophets. (Yes, I'm being helped out by Wikipedia here.) Some of the books in this category are of history, though "history" is being defined kind of loosely; the Book of Judith isn't in either the Jewish or Protestant texts, because of its historical unreliability. (The Roman Catholic and the Greek Orthodox include it, though.) On the other hand, it's a thrilling tale of how a Jewish widow charms and then decapitates an invading Assyrian general, which makes it quite a good read.
The historical books of the Nevi'im are followed by the "wisdom books," and then by the "major prophets" and the "minor prophets" (who apparently get lumped into one book in the Jewish Tanakh). The final section of the Tanakh is the Ketuvim or "Writings" (the term Tanakh is actually an acronym of Torah, Nevi'im, Ketuvim). This is where you get bits like Psalms, Proverbs, etc, if you're organizing things the Jewish way; if you aren't, then these are stuck into other categories, like the wisdom books or the major prophets.
It's worth digging through the Old Testament to see where various well-known stories come from. Samson and Delilah, for example, are out of the Book of Judges, which is in that historical grouping. Solomon (you know, the wise one) is in 1 Kings and 2 Chronicles. Job's easy to find; he has his own book. Then there are the stories you might not know, but which are interesting to read; Maccabees gives you a war story, where Alexander the Great is conquering Judea.
I have to say that the stories of the Old Testament are fertile ground for retellings if you're not afraid of stepping on people's religious toes, and they haven't been beaten to death in fantasy the way fairy-tales have. (Yes, I know I've retold more than a few fairy tales myself.) For instance, imagine the Genesis story of Noah novelized in the manner more commonly applied to meteors hitting the earth or plagues wiping out most of mankind. It has such apocalyptic potential!
There are other things to get from reading it, though. Some of them are exemplary: if you want to write fake religious scripture for your setting, you would do worse than to model it on this. Some of them are cultural: Exodus, for example, shows a stellar example of a God who has His particular chosen people, and who favors them above all others. It's a rather different beast from a God who is equally for all peoples, regardless of race. Some of them are aesthetic: the Song of Solomon (or Song of Songs) is a beautiful poem about love, which might be about married couples, or might be a veiled criticism of Solomon, or might be a description of God's love or God's love for the Israelites. (See above about God playing favorites.)
Regarding aesthetics -- which translation should you read? Since I'm recommending you read this for artistic and not theological purposes, I say the King James Version. It's heavy on archaisms that obscure the meaning, and I believe there are plenty of other reasons to criticise the translation from the viewpoint of accuracy, but the language is glorious. It has a gravity to it, a dignity, that modern translations simply lack, in my experience. If you're afraid of archaisms, and are reading mostly for the plots of familiar Biblical stories, then try something else, but I cannot recommend highly enough the experience of immersing yourself in this language.
So that's it for this year. Three years of recommendations, and though I've occasionally fallen behind by a month, I've yet to miss one. What's in store for next year? You'll just have to wait and see . . . .