Flawed tale from Nobel laureate; The Twyborn Affair, by Patrick White. New York: Viking. $14.95.

The power of Patrick White's imagination and the sonorous intricacy of his prose are the essential elements of a literary art that earned him the Nobel Prize for literature (1973). Earlier he had produced several memorable picturings of his native Australia (such as "The Aunt's Story," "Riders in the Chariot," and "The Vivisector").

Unlike many Nobel writers, White has continued after the prize to do significant work. His 1977 novel, "A Fringe of Leaves," was a richly textured reimagining of a true story of shipwreck and survival, and an eloquent commentary on the conflict between "civilization" and "savagery."

His newest novel springs from a far more challenging conception. Its hero, Eddie Twyborn, is a traumatized bisexual, in flight from the consequences of his confusion of gender, living three separate consecutive "lives." The book cannot be summarized without being made to sound absurd. To be sure, there's enough wrong with it to send many readers muttering back to Barbara Cartland.

First we see Eddie as Eudoxia, the young mistress of an elderly Greek millionaire at a luxury hotel on the Riviera. Book Two returns him to the outward form of Lt. Eddie Twyborn, a decorated hero home from the Great War, returned to his family in Sydney. Eddie's attempt to enter an "aggressively masculine world" (on a sheep ranch) founders. In the novel's final section, set in London just before World War II, Eddie has become Mrs. Eadith Trist, proprietress of a thriving brothel. At the story's startling (and moving) conclusion, Eadith's acceptance of "her" "twice born" nature immediately precedes (indeed, it seems to precipitate) the war's inevitable devastation.

Strain is evident not only in the book's overall conception but in White's heavily omniscient prose. The aristocrats who amuse themselves by patronizing Mrs. Trist's establishment are themselves patronized by White's lumbering (and pointless) satire. The dreams that haunt Eddie in all his incarnations are both impossibly lurid and annoyingly "literary." And White sometimes abandons drama, while overworking to convince us that these unlikelihoods really could have happened.

And yet the novel throbs with brilliantly rendered landscapes and painfully felt life. Though Eddie remains essentially abstract, several minor characters (such as Mrs. Peggy Tyrrell, the Wife-of-Bathian mother of 17) are wonderful -- and wonderfully used; specifically, their sense of Eddie's "strangeness" seconds , as it deepens, our own.

The essential mysteriousness of Eddie's experience remains teasingly intact. Does his bifurcated sexuality, for example, stand, simply, for the divided and troubled nature of humanity? In at least one passage, sexual differentiation is made to parallel the difference between active and passive participation in life (some of the sexist nonsense, one should add, White has derived from D. H. Lawrence) -- or, perhaps, between living life and writing about it.

The implications are clearer (though scarcely less complex) in the likening of sexuality to "regeneration of a kind" -- if I correctly understand the dreamy intermingling of religious images (descent of dove and crown of thorns): When White connects transscendence with sex, he's saying this is the onlym such heightening of their reality of which humans are capable -- a few ecstatic instants free from the muddle of selfhood, followed by an inevitable plunge back downward into knowing what we are.

If Eddie/Eudoxia/Eadith were a fully drawn and believable character, then this relentless image of nihilism might have made another of White's nearly great novels. As it stands, I'd guess that the book's frequent force will override objections to its manifest slackness and silliness -- and compel many readers to wrestle with its uncompromising insistence that we are all "divided" and imperfect people. Of course, the unevenness of "The Twyborn Affair" reopens questions about White's stature that "A Fringe of Leaves" had apparently laid to rest.