THE STRANGER AT THE PALAZZO D'ORO And Other Stories.

THE STRANGER AT
THE PALAZZO D'ORO
And Other Stories.
By Paul Theroux.
296 pp. Boston:
Houghton Mifflin Company. $25.

AT the center of the novella from which Paul Theroux's 25th work of fiction takes its title is an aging countess whose vanity demands the service of a young lover. The three other stories concern the fate of successful and respected older men who, helpless to temper their sexual desire, can only watch as it drives them toward financial or emotional ruin, or both.

In 1962, Gilford Mariner, the narrator of ''The Stranger at the Palazzo d'Oro,'' arrives in Taormina, Sicily, the resort town where D. H. Lawrence once lived and wrote and where Mariner, a 21-year-old aspiring painter, expects to revel in a similar climate of inspiration and sophistication. It's no coincidence that the writer he's reading is Lawrence or that the poem we're told Lawrence wrote in Taormina is called ''Snake.'' If there isn't an actual tree of knowledge growing in the garden of the palazzo, there's an almost audible hiss of temptation.

An archetypal young American eager for the aesthetic and sexual initiation that can, he thinks, be accomplished only in Europe, Mariner has a ready appetite for glamour. Thus he is immediately fascinated by the sight of two attractive people he assumes to be lovers. ''I want your life,'' he thinks with envy of the couple, who project the aura of polish and ease that he intends to cultivate for himself. Too far distant to really see the man and woman in their self-consciously picturesque clothes, Mariner falls prey to those four words, which will be repeated with the incantatory power of a spell -- or a curse -- resonating backward and forward in time and transforming lives other than Mariner's. Narrating what he calls ''my only story'' from the vantage of the ''golden age'' of 60 -- an age that here acquires a burnish of decadence rather than wisdom -- Mariner makes it clear that youth and envy are the constant elements in a narrative filled with allusions to the darker aspects of fairy tales.

''A Judas Memoir,'' told in four parts, also takes sexual awakening as its theme. Its narrator, a New Englander called Andy, recounts a series of episodes from his childhood: his pursuit, capture and loss of a girl named Evelyn Frisch; the role he plays in avenging the homosexual molestation of a friend; his inadvertent discovery of the adult world of sex and betrayal. Although all of these dramas unfold within the embrace of a Boston Catholic parish before Andy is even a teenager, they explore the same sort of transaction that takes place between Mariner and the countess at the Palazzo d'Oro: innocence traded for sexual knowledge and the defenses it requires, especially deceit.

Like the title novella, ''An African Story'' concerns the fortunes of an artist, this time a literary one. Lourens Prinsloo, who believes he is ''an imaginative and prolific writer because of his powerful sexual instinct,'' falls in love at first sight with Noloyiso, a black schoolteacher who, he fantasizes, ''would always look as she looked today, as lovely, as young, with the same glow of health.'' A prosperous farmer in the Transvaal, married and the father of two grown sons, Prinsloo considers happiness ''not a fit subject . . . banal,'' and embarks on an affair that will, he anticipates, grant him a second youth and inspire his writing -- a fantasy transformation for which he ends up sacrificing wife, sons, land, money, respect, even the career he hoped to rekindle. Prinsloo lives out what he himself understands as the ''most African of African stories'' -- ''a white man who had made a whole life and abandoned it upon falling in love . . . with a black woman.''

The price of sex will not be quite so high in the book's final story, ''Disheveled Nymphs.'' Its central character, Leland Wevill, is a lawyer who has retired to Hawaii and lives alone surrounded by his vast art collection, amusing himself by testing the depth of his visitors' ignorance about these treasures. For Wevill (who cannot have been given the name of a ravenous pest by accident), the attempt to seduce the daughter of his Hawaiian housekeeper will grant him a measure of satisfaction -- before it exacts the same price that sexual ''knowing'' did in the Bible: eviction from paradise.
At first glance, it would seem that an aging predator, both exploitative and pathetic, drives the plot of all four of the narratives in ''The Stranger at the Palazzo d'Oro,'' and yet the only effective protagonist in the collection, in terms of an active force that moves drama toward denouement, is a talking snake as old as Genesis. Invisible to the reader, underestimated by the antihero, lust tempts Theroux's characters with the very things it ends up taking away, youth and a sojourn in paradise. Even the child in ''A Judas Memoir'' suffers expulsion from the protected garden of family life when he's caught looking at a little girl urinating in his backyard. After being thrashed by his father (who calls him filthy and yells for him to ''Get out!''), Andy considers the punishment just and recognizes that it means he is now ''on my own and in the world.''

The tone of the stories in ''The Stranger at the Palazzo d'Oro'' is clinical and fatalistic, making it difficult for the reader to experience much engagement with the characters. Rather, each narrative is sustained by the suspense inherent in sexual pursuit (perhaps especially when we know it will end miserably) and, oddly, by Theroux's use of stereotype to sketch the more minor players.

The unfaithful housewife who has midday sex with the milkman; the priest who pays little boys to let him touch them; the chin-whiskered nun who is an overt sadist; the rich man who dies ''by hanging himself from the door handle of his Lexus with his Hermès tie''; the homosexual plastic surgeon who sees women as potential projects to be restored; the dark-skinned African woman who promises pleasures the white wife cannot -- all of these provide narrative toeholds in a landscape over which the reader might otherwise stumble.

Less effective is sex that sinks from formula toward soft porn. In one of the more quotable passages, Mariner speaks of an interlude with the countess and likens her smell to ''damp feline fur and hot blood.'' In the same story, her status as a sexual object is visually cued by props like a pair of lace gloves. (They stay on during intercourse.) In two of the four stories, desire arrives at the sight and ''songlike sound'' of a female urinating.

What is the reader to make of fiction that underscores men's dumb lust and women's emotional opacity, not to mention their fatal, black-widow power? Theroux's characters have our attention, but not our sympathy. Like Allie Fox, the brilliant, mad and charismatic hero of ''The Mosquito Coast,'' the men in these stories self-destruct while the women survive. Unlike Allie, they don't have to venture out of bed to meet a tragic end.