IN THE FLAMBOYANTLY clever West of Sunset, Dirk Bogarde's third novel, Southern California has begun to turn to rot. This should come as no surprise to camp followers of the Hollywood novel, who have witnessed those face-lifts drooping for years. But Bogarde's tone is distinctive, both compellingly acrid and more than a little creepy. It's like a whirlwind Dirk Bogarde movie -- if that's not a wild contradiction in terms.

West of Sunset is basically a European drawing- room drama interrupted regularly by what the ,emigr,es in Hollywood view as the vulgarity of L.A.: "Obese young men everywhere jogging with Alsatian dogs, police sirens all night, rape and pillage all over the place, women shopping in curlers, quite unashamedly, even in the smartest places." The culture clash primes one for comedy but Bogarde's characters are stuffed-shirt serious and spend much of the time purse-lipped and unamused -- which, of course, often pokes the reader into unintentional mirth. But, while these old guard Europeans are elitists, they are also pariahs, living on both the social fringe of Hollywood and the literal fringe -- in Brentwood, which "everyone" mistakes as being "west of Sunset."

The long opening of the novel takes place at a dinner party -- more like a mad hatter's tea party -- on the eve of Reagan's inauguration in 1981. The hostess, appropriately named Alice, is the widow of Hugo Arlington, a poet raised to mythic status after the publication of Treblinka Trilogy, a "kind of hard porn Don Juan." Each guest has an odd, symbiotic relationship with the dead poet, including Jonathan Pool, a British novelist who has come to Hollywood to discuss a screenplay adaptation of is best seller. Pool, referred to contemptuously in the past by Arlington as "The Eunuch Scribbler," could that night claim Alice, whom he has worshipped from afar for years, as his. Instead, he impetuously falls for one of the other guests, Lea Rooke, a romantic clinch Alice dismisses, astutely, as "a sort of jelly-baby-love-affair."

As each of the eccentric guests makes stage entrances ("I'm Sybill Witt. I dance and sing in a desultory way"), it becomes apparent that one is in for a long evening, and so many attitudes are struck and memories evoked -- to say nothing of brandy being served -- that the confused reader may feel adrift. (It's like My Dinner With Andr,e with six Andr,es.) One is prodded out of this not unpleasant stupor induced here and in the dialogue-drenched lunches which follow when someone says something not playfully profound but really interesting, as in a discussion of Americans attracted by the L.A. lifestye: "People searching for identity, for roots, but at the same time destroying their individual pasts."

Bogarde finds his theme here: the proud Europeans celebrate their pasts by examining themselves in relationship to Hugo Arlington throughout the rest of the book. This is the only device which pushes the narrative along, and Bogarde is careful to drop a new Arlington sin (cocaine addiction, humiliation by prostitutes, murder) every 20 pages.

While the Europeans find their individual truths in their pasts, Bogarde is not charitable to his American characters who may have wiped the slate clean and found an identity in a self-created future. A philistine Jewish Hollywood producer and his renovated wife are easy targets, even though the antenna tuned toward the grotesque is acute. ("Her hair was an astonishing confection of golden loops and twirls, towering over her bland face like a cushion . . .") And a stereotypical black laundress and her sister's running commentaries ("He tied up there, i that old room, like a sack of mail, the girls kickin' him . . . and he screaming for mercy.") seem like an Aunt Jemimah Greek chorus. After this insensitivity, it doesn't seem cricket that Jonathan and Lea would continually and insistently bait the great unwashed into making racist or anti-Semitic pronouncements so nobility could be further appalled.

However, the sour, superficial portraits are as forgettable as the full-blown European characterizations are memorable -- almost as delectable as in Bogarde's extremely well-received first novel, A Gentle Occupation. (Alert readers will recognize West of Sunset's Lea and Nettles as the daughter and friend of Captain Rooke, the hero of Occupation.) The Citizen Kane-type mystery of Hugo Arlington is merely a pretext to thread together the dozens of vignettes -- the Bogarde specialty -- many of which are self- contained marvels of characterizations and caressing dialogue.

In the best one, an exquisite set piece, the 83- year-old Countess Irina Miratova (who holds all the cards to the Arlington mystery) goes to visit her only regular social contact with the outside world, Alexi Andreyev, a spy "with all the pretensions of good manners and grace, but with none of the charm." After Irina pours an ounce of vodka from her perfume bottle into her tea, Alexi, who has had enough of her condescension, suggests gently that Irina is a "cog" just like he. Irina, who had befriended Einstein and had had Stravinsky play "Three Blind Mice" on her piano, is amused and, of course, devastated: her usefulness as a Soviet informant as well as a woman has ceased to exist.

The conversation, with its ambiguously cruel subtext, is one of those short stories -- or incidents from perhaps a less than entirely successful novel (like West of Sunset) -- which nag at you and linger on in your memory, until it becomes part of your own history.