Here’s to You, Senora Robinson : IN PRAISE OF THE STEPMOTHER<i> By Mario Vargas Llosa translated by Helen Lane (Farrar, Straus Giroux: $18.95; 148 pp.) </i>

Advancing age tends to rearrange the eyesight so that in order to see the page clearly, you hold it farther away. After grappling intimately, stylishly, with the aching turbulence of Latin America, the Peruvian novelist Mario Vargas Llosa has taken a witty distance to construct a lucid literary artifact.

“In Praise of the Stepmother” is a toy, but rather on the order of the gold clockwork nightingales in Yeats’ Byzantium. It says a heartlessly lofty thing or two about human folly, though it has a good deal of fun, some lascivious, in doing so; and imparts it to us as a Japanese chef might impart a blowfish: pleasure on the edge of poison.

The story of the exquisite Don Rigoberto, his beautiful and susceptible second wife, Lucrecia, and her golden-curled, limpid-eyed little stepson, Fonchito, is a comically cautionary tale. Rigoberto arranges himself an earthly paradise; it implodes on him. Build yourself a better mousetrap, and you will inevitably fall into it.

Rigoberto is the dull though prosperous manager of a Lima insurance company. Thedullness is like the facade of a Spanish-colonial house: uncommunicative white walls, iron-barred windows and, in the interior, a flowering patio with songbirds. As a youth, Rigoberto joined Catholic Action in order to fashion a more perfect world. Now, middle-aged, he labors devotedly to fashion a perfect world for himself in the castle of his home.

Perfection means assiduous cultivation of his body: his health, his toilette, his excretory functions. Like an alchemist turning lead to gold, he spends hours each evening cleaning, pumicing, trimming, polishing and perfuming himself. All this perfecting, this body worship, has as its object the bodily worship of Lucrecia, and the achievement of superb nightly orgasms.

Rigoberto and Lucrecia are labored over--by Rigoberto; we shall see about Lucrecia--with the inspiration that goes into a work of art. To assist his fantasies, Rigoberto has collected erotic paintings, prints and texts. And the successive chapters of Vargas Llosa’s brief book--as polished as Rigoberto’s armpits, or his talcumed feet that give off “a slight, virile odor of heliotrope at dawn”--meld the story with selected paintings.

Colored plates of these, mostly celebrated and sensual, are inserted for the reader. The effect of Jordaens’ Gyges and King Candaules spying on the king’s bathing wife, of Boucher’s “Diana at the Bath,” of Titian’s “Venus With Cupid and Music” as successive keynotes for the text is not illustration so much as a gently sardonic hyperinflation.

Rigoberto, for example, who among other fixations is specially fond of buttocks, proclaims himself to Lucrecia as King Candaules showing off to Gyges the splendid proportions of what he likes to inflame himself by calling his wife’s “croup.”

The thing about fantasies, though, is that everyone can play. Lucrecia acts out Rigoberto’s with wifely devotion, but she has her own. She too sees herself as Venus, but a Venus whose particular arousal comes not from her lord and master but from the Cupids fluttering about her. The cover of the book--a detail from Bronzino’s all-but-drooling portrait of the goddess in high excitement from the child tweaking her nipple--clearly foretells what will happen.

Fonchito will. Beautiful as a cherub, amoral as the tiny love-god, malevolent as a vengeful Puck, he seduces his stepmother. More exactly, he helps her to seduce herself. What comes of it need not be described here, but at the end, Lucrecia has been thrown out, Rigoberto has turned to prayer and mortification--we are helpfully offered Fra Angelico’s “Annunciation” as the final colored plate--and Fonchito reigns.

“Fresh, round and full, childish, his laughter drowned out the sound of the water in the washbasin, appeared to fill the whole night and mount to those stars which, for once, had appeared in the muddy sky of Lima,” Vargas Llosa concludes.

The author is silky; so is Helen Lane’s translation. Vargas Llosa has written a genuinely erotic story and a marvelous parody of one. The epigraph by Cesar Moro strikes precisely the note of Gallic intellectualism that he seeks: sex as discourse, with roots going back to Laclos and Sade:

“It is only natures entirely given over to vice whose contours do not grow blurred in the hyaline mire of the atmosphere.”

From there we get the foolishly exalted comedy of Rigoberto’s absolutions. At stool, he conducts a delicate rite of purification. “You’re gone, you rascal you,” he interpolates the results, “and can’t ever return.” Fantasies of perfection are punctured by fantasies of beastliness. A deformed face by Francis Bacon allows him to imagine himself as a monstrous, boil-inflamed nose, seducing women by allowing them to confront their own secret shames and fears of ugliness.

Lucrecia’s transports with Fonchito, equally parodic, are less amusing; probably because, more innocent, she will be the more abominably victimized. Paradoxically--eroticism is paradoxical by its nature--they are more genuinely sexy.

In fact, Rigoberto’s lucubrations are not really about sex at all, but about power. If Vargas Llosa’s toy has a message beyond its inveigling clockwork, it is here. Behind the macho is the solipsist. The Spanish yo is the strongest and most assertive of first-person singulars; much more so than the frailer English I , the French je, the German ich.

Rigoberto’s ultimate fantasy concerns not fornication but reigning alone, untouchable, immune to any external contingency. If you cannot rule the world, you can dictate to your body, your senses, your bedchamber. Is Vargas Llosa aiming at the ungovernability of a male society made up entirely of one-subject dictators? Somewhat, I think. In any event, Fonchito is an agent of revolutionary chaos that goes far beyond Don Rigoberto’s perfumed domestic arrangements.