AFTER THE REUNION. By Rona Jaffe Delacorte. 331 pp. $17.95.an Dooley

RONA JAFFE's best seller The Best of Everything was published before the days of women's liberation. The bright young things who starred in her first novel had bounced into New York from Small Town USA and though they were ostensibly looking for work, in truth their eyes were straining up and down the Avenue, hoping to catch sight of Mr. Right. They had barely rented their overpriced apartments and begun their underpaid jobs before they learned that Mr. Wrong, cad that he is, likes to dress up in Mr. Right's clothing. The book was full of false lovers, who, having taken what in those days was still considered a pearl beyond price, left the ladies alone and crying.

Plus ca change, plus c'est la meme chose. The women in After the Reunion have reached middle age but they're still getting it in the shin. It's husbands, this time, and what a lot they are. There's the gorgeous Alexander who loves his wife, Chris, but loves young men more; the chilly Richard, dealing out a perpetual game of Happy Families; Cokehead Ken, who plays games too, but kinky ones. The ladies who've drawn these loutish lads were all classmates at Radcliffe, and they -- and the unmarried and glamorous Annabel -- come together as each faces a crisis that changes her life.

This time the theme Jaffe plays for her women to dance to is the liberation limbo: "We survived not only our mistakes, but our misguided little teen-aged dreams, and the shattering of those dreams, and went on to become happier and more interesting than we ever imagined," says Annabel, in a toast at the end of the book. "You remember in Peter Pan when Tinker Bell is dying, and Peter turns to the audience and tells them to clap ther hands if they believe in fairies; and everybody claps their hands, and Tinker Bell's life is saved. Well, clap your hands if you believe in surprises, and the life you save will be your own."

The women in After the Reunion are great believers in the clap-your-hands route to success, and why not? When Emily is thrown out by the dastardly Ken, she spends a brief time living the life of a well-supported ex-wife before remembering that nothin' says lovin' like something from the oven. She then becomes an overnight business sensation as the force behind Emily's Cookies, trotting into Media Land wearing a new wardrobe and a facelift.

Daphne, the beautiful golden girl; Chris, the brilliant editor and ultimate in New York chic; Annabel, "absolutely knock-out gorgeous" owner of a fashionable boutique: they are all extraordinarily well endowed and extaordinarily well provisioned, moving through a world where the champagne is Dom Perignon, the caviar beluga and the trinkets come from Tiffany's. They are women for whom, "New York is an enormous candy store filled with tantalizing things to buy," and how can you resist when "Merriment screams at you from every shop window"?

Why do these women, cushioned by the current status symbols, given trendy, successful careers by their creator, seem so hopelessly dated? It's not their name-brand nonsense; heroines in romantic fiction always announce their well-being through their belongings. How else are we to know that they are to be envied? It is that these women, like those in Jaffe's first book, are victims. And once again, the wicked ruler is man. Daphne adores Richard, though she frets because, "Richard always gave away everything that wasn't perfect. . . . Richard's whole life was Rashomon . . . . He tiptoed considerately through lives he had wrecked, smiling his glittering, winning smile." Timid Emily recalls that when she "tried to put Ken's things away, or do things for himould turn on her and say she was smothering him, and if she left his bag where it was he would come home and accuse her again of being a parasite."

When Jaffe does create women who are not being victimized by men, she does it by role reversal -- the woman becomes the sexual exploiter. Here is Annabel with her penchant for young men: "He was hers: the hard smooth muscles under the silky skin of his lean young body. . . . The downy cheekbone that had been forbidden across from her at the tiny table in the cafe. . . . They devoured each other with all the greed and yearning they had been hiding during their civilized mating dance." Kit, Emily's daughter, also believes in communing with the masses: "The guy she'd brought home last night was gorgeous but stupid. His name was Rick, and she'd forgotten his last name, if he'd even told her, and after (naughty word) all night it would be gross to ask now."

The book lollops along from woman to woman and crisis to crisis, dragging in drugs, sex and teen-aged suicide, but despite being decorated with such timely tinsel, After the Reunion is like a yearbook dragged down from the attic -- cause to giggle at the way we were.