The Worm Ouroboros is the best fantasy of the 20th century. At this point, for me, the only competitor is either of the first two Gormenghast books. (It takes a contrarian to call the third book “good.”) Very few people have started Ouroboros, and I’d wildly guess about 1 in 10 of those people has finished it, and those few people may, like Tolkien, find its unequivocally pagan worldview repulsive. So I am in the tiny minority as an avowed Ouroboros partisan.
That said, Ouroboros isn’t the most interesting of Eddison’s works. It’s the best, but it’s not the most interesting. Floridity notwithstanding, Ouroboros is straightforward. As is the case in Barker’s Jakalla, the crux of morality isn’t “good” against “evil,” it’s nobility versus ignobility. In this case, nobility lies in playing one’s part boldly. Villains of the blackest stripe can be heroic in their dastardy; bald-faced oathbreakers can be heroic in their treachery; but there is no heroism in poltroonery or sentimentality or half-measures. The characters don’t grow. Of course they don’t fucking grow, and in this case they literally do the opposite. They’re typal and they aren’t “deep” any more than Achilles or Styrbjorn is deep. (Hector? Solid guy, wouldn’t last a second in Demonland.)
Nope, Eddison’s most interesting work is the Zimamvia trilogy, brought to the modern mass spotlight by the Ballantine Adult Fantasy series. (Just like the Gormenghast books and The Night Land. Lin Carter is well-shriven of any literary sins.) It’s a bit of a mess, although that’s often the intention. The timelines are fucky, the characters aren’t necessarily who they are, the setting isn’t necessarily what it is, and there’s a shitload of repartee, and soliloquizing, and speculation, and Spinoza. But you get a thorough explication of Eddison’s personal philosophy, which is arch-pagan in a far more nuanced way than the epic/saga homage of Ouroboros. Ouroboros does not fuck around with meandering dinner table metaphysics because that is nerd shit. Zimiamvia wallows in it, and it isn’t perfect but it is awesome.
The volumes’ publication order is the reverse of their internal chronological order (to the extent that has any meaning at all in the context of the stories). They should be read in the order they were published. The third installment was never finished, although Eddison did leave behind a fragment and thorough outline.
The Zimiamvia books are not in the public domain and they are relatively obscure, so for a very long time, there were two ways you could read them: in moldering BAF paperbacks or in a loathsome “annotated” Dell omnibus. Now you can get them in a very nice e-book version HERE. This makes life a lot easier on me, because my BAFs really are spore-ridden pieces of shit now. And happily enough, you also get Ouroboros, billed as a precursor to the Zimiamvia books, which it is in no way whatsoever. (Zimiamvia is mentioned once in passing, and the guy who pops up at the beginning of Ouroboros and never shows up in the book again and every plebeian reviewer bitches about? He’s the franchise, boys.)
I doubt anyone will read Zimiamvia on this recommendation, but I can hope. If you haven’t read The Worm Ouroboros, it’s more important that you do that, and I urge you to give it another run if you tried it before and didn’t like it. This is also how I pester people about Robert Aickman.
(Ouroboros is, however, completely useless for D&D purposes. It does not correspond in any way with that level or tone of adventure, it is not within horizon’s distance of S&S or weird fantasy, and there would be nothing more offensive to Brandoch Daha’s sensibilities than a grubby little caucus of Cugels.)