Ursula K. Le Guin's beautiful, haunting new novel, due out in the UK in May 2009, has already been published in America. Accordingly, the bound proof I read came pre-endorsed for the Britreader: "a winning combination of history and mythology featuring an unlikely heroine imaginatively plucked from literary obscurity" (Booklist). That rather undersells it, actually. "Deserves to be ranked with Robert Graves's I Claudius" (Publishers Weekly). That's more like it. Although Le Guin's pre-Roman first person narrative has a very different flavour to Graves's Imperial Roman first person narrative, they are of a similar stature: classics in essence as well as theme. "Arguably her best novel" (Kirkus). Arguably so. Certainly I enjoyed this novel more than any Le Guin since the 1970s; and that (it's almost tautological to add this) means that I enjoyed it more than pretty much any novel since the 1970s. It possesses a depth, clarity and wonder greater than most of the fiction being published nowadays.

Lavinia is a Latin princess, living in pre-Roman Italy. She was the woman who married Aeneas, the Trojan prince who fled his burning, defeated city to settle his people and his household gods in a new land. Virgil's Aeneas. To be precise, Virgil's Aeneid ends (with Aeneas's killing the local warrior Turnus in a sudden and deplorable loss of self-control) before his marriage to Lavinia, but since his and her descendents are destined not only to found Rome but to rule it and the world as Caesars, we know the marriage is coming.

The Aeneid (a genuinely core text, I need hardly remind you, of western culture) divides broadly into two. Books 1 to 6 are sometimes called "Virgil's Odyssey," since they detail Aeneas's escape from Troy and his voyages around the Mediterranean in search of another homeland. Fate has decreed he will settle in Latium, in central Italy, and at the beginning of Book 7 he and his people finally pitch up there. Books 7-12, the second half of the epic ("Virgil's Iliad"), reconfigure Homer's famous epic of war: instead of Trojan Hector fighting Greek Achilles, it is Trojan Aeneas fighting Latin Turnus, and instead of Achilles winning, Aeneas triumphs. Le Guin's Turnus dies by p. 160 of her 250-page account, which is to say, her treatment overlaps. She gives us "Le Guin's Virgil's Iliad" in the first half of her novel, followed by "Le Guin's Livy's Ab Urbe Condita" in the second. Her voice, very different to but just as strong as Virgil's (and capable of much more variety), inflects her source in fascinating ways.

Indeed her reworking of Virgil involves more than just the Aeneid: the poet is a spectral character in, as well as the textual frame for, her narrative. It's all exquisitely done, as another pre-endorsement put it:

Everywhere Le Guin catches the rhythms of the great epic, echoes them, riffs. In a way, this is a jazzy book, playing in odd syncopation with a massive canonical work ... I found myself delighted, even stunned, by the freshness of Le Guin's prose. (Los Angeles Times)

Enough quoting other reviews, even to endorse their judgments. Because actually, although her prose is extraordinarily fresh and effective, "jazz" isn't the right comparison to make here, I think. There is a stately sureness of step to Le Guin's writing, beautiful, mournful, and plain, more like a late Beethoven string quartet than Keith Jarrett.

Le Guin clearly knows the Aeneid backwards (knows, we could say, the Dienea), so clearly she knows how slight a figure this heroine makes in Virgil's account. When "Lavinia virgo"—the maiden Lavinia—crops up in the original poem, her eyes are demurely downcast ("oculos deiecta decoros" 11:480). The most Virgil does by way of description is to say how very prettily she blushes ("Lavinia heard her mother's words, her burning cheeks steeped in tears, while a deep blush kindled its fire and mantled o'er her glowing face. As when one stains Indian ivory with crimson dye, or as when white lilies blush with many a blended rose—such hues her maiden features showed." 12:64ff.: I'm quoting the Loeb translation here). That's just about it for Virgil's interest in Lavinia, except that in book 7 her hair catches alight in a miraculous portent of her future greatness, and the oracle says that she must not marry a local, but must wait for a foreigner ("Strangers shall come to be thy sons, whose blood shall exalt our name to the stars and the children of whose race shall behold where the circling sun looks on either ocean, the whole world rolls obedient beneath their feet" Aeneid, 7:96ff.). Indeed, despite being the ostensible cause of conflict between Aeneas and Turnus, she's so minor a player in Virgil's poem that K.W. Gransden's critical study of books 7-12 of the Aeneid (Virgil's Iliad: an Essay on Epic Narrative, Cambridge University Press: 1984) doesn't even mention her once.

Out of this unpromising raw material Le Guin has done something very clever. She has taken a marginal figure as a means of reflecting upon a great work of literature without thereby writing a novel about the marginal—as, for example, Marion Zimmer Bradley did in her Morganacentric Arthurian novel The Mists of Avalon (1979). Bradley's enormous novel is at heart a polemic about the marginalisation of women; and, in its way, a powerful one. But Le Guin, though of course aware of the limitations of female existence and the arbitrariness of male power, has a broader aim in this novel. What she has done is to evoke the actual quality of lived experience: the qualia of people and their being-in-the-world. It is life, in the sense of that thing that goes on from day to day, with all its variety, its joys and anxieties, that is the heart of this novel. Lavinia is the best person to focus this perspective because she is not, as many of the male characters are, distracted by grandiose stories of Fate or Destiny, Pride or Honour; she has the clearest perspective on life as a whole. That's what comes across in the fiction. She lives, sees war come to her country. She sees Turnus killed, and then marries Aeneas and has a happy marriage—that rare quantity in contemporary fiction, beautifully and convincingly rendered here. Then she sees her husband killed, and goes on with her life, coming under the authority of his heir, her stepson Ascanius. She negotiates the awkwardness and danger of that relationship. She raises her own son Silvius. She grows old.

In addition, Lavinia's world is interpenetrated with the supernatural—with omens and prophecy, with the ghost of a poet not to be born for centuries, and with an ending in which (spoiler redacted). But what I would say about this is that, unlike most Fantasy, where the magic exists discretely as a glamour or addition to an otherwise mundane mis-en-scène, Le Guin's pre-Roman Italy is rendered as a place where the distinction between the mundane and the magical doesn't really obtain. The magic feels completely natural, and as a consequence the natural world becomes magical. This is a much more remarkable achievement than I am perhaps suggesting, because Le Guin achieves it despite wholly jettisoning Virgil's gods and goddesses, so important (and so liable to intervene in the doings of humans) in every book of the Aeneid. Le Guin's author's note puts it plainly: "the Homeric use of quarrelsome deities to motivate, illuminate, and interfere with human choices and emotions doesn't work well in a novel, so the Graeco-Roman gods, an intrinsic element of the poem, are no part of my story" (p. 253). This is a very good call. It means, amongst other things, that the magic in Le Guin's novel is not anthropomorphized, and therefore not particularized, except in the localized sense that it clings particularly about certain landscapes, about certain families and communities. Instead there is a pervasively numinous quality to Le Guin's imagined world; finely rendered and completely believable, it makes for a brilliantly compelling textual universe.

Putting Virgil himself into the narrative as a character is a bold move. It works, not despite but because it turns the novel into a self-reflexive meditation upon poetry, or writing more generally. Aeneid 6 ends with Virgil's famous, but nevertheless rather baffling, distinction between true dreams and false dreams, the one set emerging from the underworld via a gate of horn, the other via a gate of ivory. Le Guin's Virgil frets over his own veracity, or validity, when he appears before Lavinia. "I am a wraith ... my body is lying on the deck of a ship sailing from Greece to Italy, but I don't think I'll get to Brundisium even if the ship does. I am sick, I'm dying ... or else I am a false dream. But they come from down under there, don't they, the false dreams? They nest like bats in the great tree at the gates of the kingdom of the Shadows, so maybe I am a bat that has flown here from Hades. A dream, that had flown into a dream" (p. 39). Bats fly, but they don't fly straight.

Against the hesitant figure of Virgil, and the intricate, backward-spiralling verse-narrative of the Aeneid, Le Guin draws Lavinia as a narrator whose tale moves swiftly straight. No bat, but an owl: "I fly among the trees on soft wings that make no sound. Sometimes I call out, but not in a human voice. My cry is soft and quavering: i, i, I cry: go on, go" (p. 250). I love that shift from the Latin 'i, i' to the English 'I': it embodies in little the most profound of shifts from being-in-time to egotistical subjectivity. Lavinia is surrounded by people, from Virgil, to her father, to her suitor Turnus and her stepson Ascanius, who trace out their lives in spiral tangles of ego. Lavinia herself sails through, always conscious of the fact that the key salient for life is not that it coalesces around particular moments, or particular subjectivities, but that it goes on. It is this that makes narrative the key mode of art for apprehending life. That's why Le Guin's story rolls smoothly not only past the death of Turnus (where the Aeneid stops), but also the death of Lavinia's loved husband Aeneas—very touchingly understated, here—and onward. That's why it ends so beautifully, inverting the solidly masculine I of I, Claudius and ending instead with the Molly-Bloomish i, i, of the hooting owl. Virgil has a story to tell, but he is a poet first, and his poem continually risks distilling into gem-like stuck moments. Le Guin is capable of very affecting poetry, but she is a storyteller first. Her novel is a narrative, and is about narrative: about the fact that life goes on after setback, disaster, and death.

It is harder to praise books than knock them. To criticize in a negative sense necessitates the self-generating structure of being specific: in what ways does the book fall short, where is it wrong? That doesn't transfer to the wholly positive review. We might ask, in what ways is this book so very good? But the temptation would be to reply: in all the ways. There's a quality to this fiction that I cannot capture in a review. You'll have to read it for yourself to find out what I mean.

Adam Roberts is a writer and critic of SF. He lives a little way west of London.