April's recommendation: the Iliad.
Last year's folklore recommendations followed a theme of works that had a profound effect on English literature. I like the idea of each year having a theme, so welcome to the Classical Year.
Like its counterpart, the Odyssey (coming soon to a recommendation list year you, i.e. right here), the Iliad is attributed to Homer, a blind Greek poet who may or may not have ever existed, per se. Understanding the composition of these poems was one of the big breakthroughs in early folklore research. You see, for a long time, the theory was that the poetic structure of the Iliad could only have been achieved in a literate context, with a poet who was writing his work down. Otherwise, how could anybody remember all the lines, let alone reproduce the various artistic qualities they held? But this contradicted the traditional story, which is that Homer was blind and oral poet. Milman Parry and Albert Lord answered that paradox with what's known as oral-formulaic theory, which explains how the poetic structures of the Iliad, far from being a sign of its literate composition, are in fact the means by which it was possible for an oral poet to recite such an epic work.
That's the short version, and I actually toyed with the idea of adding non-fiction recommendations to my series, in which case Albert Lord's book The Singer of Tales would have been last month's or next month's piece. I discarded that idea, but bring oral-formulaic theory up now because it's important to understanding why the Iliad sounds the way it does. Those repetitive formulae, the epithets which tag along with so many of the characters' names ("swift-footed Achilles" and the like), are a part of the composition process, which cannot be divorced from the performance process. They helped both the poet to compose his song, and the audience to follow the tale. Bear that in mind as you read it, and the repetitious nature of the poetry will seem less of an irritant.
Now, what about the story itself? People usually say the Iliad is the story of the Trojan War. This is not actually true.
Sing, goddess, the rage of Achilles the son of Peleus,
the destructive rage that sent countless pains on the Achaeans...
It's actually the story of Achilles' hissy fit.
(Maybe I should issue a disclaimer here that I usually find Achilles to be a whiny and egotistical little bastard.)
When the poem starts, the Trojan War has already been dragging on for ten years. All the stuff with the golden apple, Paris and Helen, the mustering of the famous thousand ships -- all that's happened long since. The poem starts with Achilles getting into a fight with Agamemnon, the king of Mycenae, over a slave-girl. As a result of that fight, Achilles decides he's not going to participate in the war any longer. Much fighting ensues, without Achilles. The gods muck around with everybody. Eventually Patroclus, Achilles' companion (good buddy or catamite, depending on which interpretation you ask), dresses up as Achilles and gets his ass killed by Hector. This pisses off Achilles sufficiently that he jumps back into the war, kills Hector, drags his body around the walls of Troy for a while, and finally lets Priam (king of Troy and Hector's father) have the body back for a funeral. And then the poem ends.
No Trojan Horse. No death of Achilles. Sure as hell no aftermath with Agamemnon going home and being gacked by his wife's lover, etc. Odysseus' adventures get their own poem. The Iliad is the story of Achilles being angry: it starts when he gets angry, and ends when he calms down.
That's a simplified version of the story, of course, but you can see that it's only a tiny fragment of what you'd expect. Most of what we know about the Trojan War comes from other sources, not from this poem. This is a little startling to people who come at it with the wrong expectations: they don't find half the things they're looking for, and (unless they're giant mythology geeks) haven't even heard of half the things that are in it. (Diomedes? Who's he? Unless you know Troilus and Cressida, one of Shakespeare's worst love stories.)
Wikipedia, which admittedly is not the most reliable source in the world, lists twenty-two different English translations for the Iliad, starting with Chapman in 1598 and going up to a 2002 version by Ian Johnston. I believe Richard Lattimore's 1951 rendition is one of the most famous, having the benefit of being in verse; I admit to a bit of a prejudice against any prose translation of something that started as poetry. Aside from that, though, I can't begin to tell you which translation is the best, as I lack sufficient familiarity with the options. My one recommendation would be to consider, not reading the poem, but listening to it. The Iliad began its life as a thing people heard, and any folklorist will tell you that written texts and oral ones are very different beasts. Annoying repetition on the page becomes a useful reminder of where you were in the text when you hear it.
Of course, there are always dramatic adaptations of it, too. I occasionally get weird looks when I admit I liked the 2004 movie Troy, but let me put it this way: as a non-fantastical story of the Trojan War that stands up on its own (not needing prequel and sequel stories to wrap up the loose ends), it does quite well. That means there are no gods and certain things go differently at the end (see above about no murders at the hands of the wife's lover), but I don't object to that. I'm not aware of any other movies or TV series, though I'd love to hear of any.
In terms of story adaptation, Marion Zimmer Bradley wrote a novelization called The Firebrand, which tells the story from the viewpoint of Cassandra, Paris' sister and the prophetess whose predictions were not believed. That's the only one I've read personally, though you can find others listed on my page of fantasy adaptations.
Whether you read it, hear it, or watch it, though, the Iliad is a blood-and-guts war story. Keep an eye on that when the poet goes into raptures over how many ships Nestor brought or how pretty Achilles' armor is, and you'll have a good lifeline through the tale.