The Soul’s Speedometer : FICTION : SLOWNESS,<i> By Milan Kundera</i> .<i> Translated from the French by Linda Asher (HarperCollins: $21; 165 pp.)</i>

If a writer is never on leave, neither is a writer’s companion. Milan Kundera and his wife, Vera, set off from Paris for a getaway night in one of those chateaux that the French have converted into inns. A little peace, a whiff of classic order, a touch of greenery (never mind that a highway runs just outside).

But another car is crowding them from behind, its driver apoplectic in his rush to exceed the Kunderas’ no-doubt-already-considerable pace. The author thinks of cars and motorcycles; he thinks of modern life, of speed and slowness and the significance of each, and how they relate to memory and forgetting. Before long, the Kunderas’ quiet night off has become a fictional shivaree. Ideas attend dressed as characters, and characters as ideas.

Replete with duck and excellent Bordeaux, Kundera lies awake populating the chateau with the 18th century Mme. T. and her lover, the chevalier; with Berck and Duberques, two present-day French public figures; with Pontevin, epigrammatic guru of an intellectual coterie, and Vincent, his worshipful and rivalrous disciple; with an international conference of entomologists, among them a Czech former dissident; with Immaculata, a celebrity groupie; and with Julie, who just wants to be loved.

Vera wants to sleep, but the characters keep trooping through the bedroom. “You’re the victim of my crazy imagination,” Kundera apologizes. “As if your dreams are a wastebasket where I toss pages that are too stupid.” Alarmed, Vera rouses herself. “You’ve often told me you wanted to write a novel some day with not a single serious word in it. A Big Piece of Nonsense for Your Own Pleasure. I’m frightened the time may have come,” she warns him. “Seriousness kept you safe.”

“Slowness” has its dangers, but they are neither a lack of seriousness nor, for that matter, seriousness. Kundera at his best (“The Book of Laughter and Forgetting,” “The Unbearable Lightness of Being”) weaves the two wonderfully together. The weakness of “Slowness” is in the warming-up process: Like twin motors on a cold morning, the author sputters sententiously for a while before smoothing into seriousness, whimsically for a while before warming into pleasure.

But he gets there. His brief novel is a playful envoi from a tender misanthrope; a rant set to music by Mozart. Kundera reprises the themes from his bigger books but the effect is of a writer not repeating but recollecting himself.

“Slowness” continues Kundera’s work of undermining the big isms; the pretension and distortions in our public life and private culture. The comic two-stroke of “Slowness”--bring a character to life and lecture to it--makes it evident why, though Kundera was an exiled dissident from Communist Czechoslovakia, some of his fellow dissidents have had very little love for him.

“Slowness” is multilayered, not a story within a story but a covey of storylets fluttering about each other, distracting, annoying, pleasing and--like the forest creatures in Disney’s “Snow White”--chivvying us where we are supposed to go. Backward, essentially.

Kundera argues against the rush of modern life and the bleaching of our slow privacies in the stepped-up glare of the public eye. He praises slowness in its various forms. There is the ambling woolgathering of indolence--the Czechs call it “looking into God’s windows”--as against the modern intolerability of “having nothing to do.”

Slowness stands for what keeps us human: memory. When we are walking and try to remember something, he writes, we slow down; if we are trying to forget something, we speed up. We use speed to escape ourselves.

So much for the philosophy drifting back through the stories that infiltrate Kundera’s wakefulness and Vera’s dreams. The account of Mme. T. and her amorous intrigues is ranged on the side of slowness; in counterpoint are vignettes of modern speed. They are comic and satiric though most of them are touched with Kundera’s characteristic tenderness.

The Mme. T. sections are an exquisitely told account of a noblewoman who brings home a young chevalier to divert her husband’s jealousy from her full-time lover, a marquis. It is one night of passion, shaped by Mme. T.’s musical use of conversation to alternately slow things down and give them free rein.

Such restraint contrasts with the headlong manias of the present-day characters. Duberques and Berck, high-minded celebrity intellectuals, are deadly rivals, not for results but for applause. The former gives a banquet for people with AIDS; he has himself photographed kissing one of the guests on the mouth, which is full of chocolate mousse. Berck ripostes by flying to Africa to be televised stroking a starving child. Duberques comes back with a nationwide candlelight procession for all starving children. Berck flies to join a popular insurrection in Asia; his geography is shaky, though, and he ends up in the Himalayas with flu.

The pair are “dancers,” explains Pontevin, a “pure” intellectual, to his disciple, Vincent. Public life has become a matter of televised vanities. But Vincent notices that when others join their cozy chats, Pontevin abandons rumination for a posturing dance of his own.

And Vincent is not immune. Attending an entomologists’ conference at the chateau--it is also Mme. T.’s and the Kunderas’--he is ignored until he manages to pick up Julie, a typist to whom nobody else is paying attention. He preaches Sade to her and, when she would happily settle for plain lovemaking in her room, decides that they must copulate publicly in the chateau swimming pool.

The Czech entomologist speaks of the 20 years he worked as a janitor as punishment for being a dissident and basks in the conference’s applause. But others lose their jobs too, Kundera remarks, without being proclaimed heroes; in fact, the scientist’s dissidence was involuntary. Paris chic chooses what it will favor; after brief attention, the scientist is ignored. His only consolation is that 20 years of hard labor have given him a splendid physique; he goes to the pool to show it off.

And there, in a kind of carnival, the various stories converge. While Vincent is incompetently attempting to have public sex and the Czech is doing handstands, Immaculata--yet another speeded-up character--attempts to drown herself in the shallow end of the pool after her celebrity hero, Berck, rebuffs her.

Morning comes, the shivaree fades out, they all depart. On the way to their car, Kundera and Vera see Vincent headed for his motorcycle. He crosses paths--the 20th century and the 18th--with the chevalier, heading for his carriage. Mme. T. used him, but she also shaped a night of slow passion and intellect in a form he will never forget. The others, speeding, will have nothing to remember.