MUCH OF TODAY'S fine prose is spare and lean, the literary equivalent of nouvelle cuisine. Nights at the Circus, while good as they come, is the opposite, a luscious and gooey dessert of a book, doled out in sinful proportions.

Consider, just for starters, the novel's heroine, Sophia Fevvers, a circus aerialiste who sports wings, friends, wings: "a polychromatic unfolding fully six feet across, spread of an eagle, a condor, an albatross fed to excess on the same diet that makes flamingoes pink." But that's not all. She's more than six feet tall with three-inch eyelashes, and eyes that burst open, "whoosh! like blue umbrellas."

Angela Carter -- among Britain's most admired writers (The Bloody Chamber and Fireworks collect her brilliant, disturbing short fiction) -- introduces Fevvers in her dressing room where "a hissing flute of bubbly stood beside her own elbow on the dressing-table, the still-crepitating bottle lodged negligently in the toilet jug, packed in ice that must have come from a fishmonger's for a shiny scale or two stayed trapped within the chunks. And this twice-used ice must surely be the source of the marine aroma -- something fishy about the Cockney Venus -- that under lay the hot, solid composite of perfume, sweat, greasepaint and raw, leaking gas that made you feel you breathed the air in Fevvers' dressing room in lumps."

Here American journalist Jack Walser has come to discover if Fevvers is fact or fiction. If the latter, he'll include her in his series of articles, "Great Humbugs of the World." Ah, but Walser wilts, falls in love, joins the circus, and thus, along with us, feels "the beginnings of a vertiginous sense of freedom."

As Fevvers admits, "it's been a picaresque life." We, like Walser, will trail Fevvers through Petersburg where, because of her, "the exhausted soul of Mother Russia stirred, a little," and deep into the Siberian wastes. First, however, Fevvers offers us her past.

There is, of course, the bawdy house where she was raised. Fevvers lingers over the stories of Ma Nelson, who ran the place, and each of the girls -- even some of the customers. Meanwhile, Fevvers learns to fly, an ability which represented, "the grand abyss, the poignant divide, that would henceforth separate me from common humanity."

After Nelson it's Madame Schreck, a bitter turn, for Nelson's had "accommodated those who were perturbed in their bodies and wished to verify that, however equivocal, however much they cost, the pleasures of the flesh were, at bottom, splendid. But, as for Madame Schreck, she catered for those who were troubled in their . . . souls." Schreck sells poor Fevvers to the homicidal Rosencreutz, who sees her as his "rejuvenatrix." Trouble is, she has to be sacrificed in order to accomplish this task.

Fabulous and madcap? Yes, but by the book's end, we'd follow Fevvers anywhere. In fact, we may well already have. We are thoroughly ensorceled, we are hers. However odd and impossible the adventure she's narrated might seem when we attempt to recount it, under the spell of her voice, we believe it utterly. We hold our breath when a Grand Duke nearly melts her down to one-pint size and, when she breaks a wing in a train- wreck, we list to one side. We are, in short, wholly engaged, sympathy and senses.

This is because everything in this novel is intense and immediate even though it is set at "the fag end, the smouldering cigar-butt, of a nineteenth century which is just about to be ground out in the ashtray of history . . . eighteen hundred and ninety nine." Angela Carter is a conjurer as much as a stylist, placing images where we never dreamt they'd be placed, and indelibly, too.

Even the minor characters -- the Princess, Mignon, the Strong Man, the clowns, the dancing tigers, and the penitent murderesses -- seem major creations. We drool thinking of a book about any one of them.

When we leave Fevvers -- "her plumage rippled in the wind of wonder" -- it is with a sense of having overindulged, though we would willingly again. Nights at the Circus, in fact, could make unrepentant gluttons of us all.