ISADORA'S BACK and Bean's got her. You remember Isadora Wing, alter-ego of the irrepressibly horny J(ewish) A(merican) P(rincess) poet Erica Jong, who gave our language the zipless you-know-what and proved, in the early 1970s, that you could be a feminist and still enjoy heterosexual intercourse? When last we saw Isadora, she had become a celebrity because, like her creator, she had written a racy novel about a horny JAP poet. Also, like her creator, she had left her Chinese-American psychiatrist husband to take u with a younger Caucasian (male) novelist. These developments occurred in How to Save Your Own Life, a somewhat dreary, though steamy, sequel to Fear of Flying.

Now, Isadora reappears as a Connecticut mother of one, pushing 40, still horny, ever the celebrity, but brokenhearted because the younger Caucasian has left her. I don't think I'm giving too much away by telling you that this doesn't stop her from bedding every fellow in sight (rabbis, disc jockeys . . . Isadora always did have smorgasbord tastes) until she falls for an even younger Caucasian (male) actor named Bean.

Parachutes & Kisses is funny and searching enough to suggest that How to Save Your Own Life was Jong's sophomoric jinx. A born hedonist burdened with classic Jewish guilt, she continues to seek the feminist way of knowledge without abandoning pleasure, intellect or honesty. Like so many of us who are her age, she is caught between two generations -- the baby-maker generation and the baby boomer one -- on the cusp of liberation. She wants independence and she wants to be cuddled. She values her success but wonders what good it is if all she gets out of it is an empty Jaccuzzi. She breeds a child while still yearning to remain one herself. She balances four-letter words with five-syllable ones. I like Isadora, even when she behaves foolishly, which happens often.

Still, when I finished this book, I recalled what a brouhaha Fear of Flying created, and wondered why. My female friends and I read sections aloud, howling with recognition, just as we quoted Joni Mitchell and wept in commiseration. I did not feel that kind of elation reading Parachutes & Kisses.

Was Fear of Flying that much better a novel? Having reread it to make sure, I think not. But it was fresh then, back in the brave new days of 1973, as were we. They were heady days and Jong was a feminist pioneer, bringing female lust out of the closet. Finally, there was a serious woman novelist who made a point of describing, in the most graphic terms and colloquial words, what sex is like from a female perspective. She gave her lusty heroine intellectual respectability formerly allowed only male heroes of the Norman Mailer variety.

Although Jong was not the first female novelist of her generation to center a novel on explicit sexuality (Lois Gould's Such Good Friends, for example, was published before Fear of Flying), she had the greatest impact. Since Fear of Flying, however, there have been a number of well-written sexy "feminist" novels (Blue Skies, No Candy by Gael Greene comes to mind). The right to have an orgasm and to read about them in non-trash novels is taken for granted by today's post-liberation young women. For those of us in Jong's generation, the elation has been replaced by anxiety about middle age, old age, and even death. As Isadora herself observes about her peers early in Parachutes & Kisses: "They are the older generation now. They know it because they sign the checks. They know it because their parents are starting to die . . . They have reached the age where they meet their new lovers at A.A.; the age where some of their friends are addicts, some of their friends are bankrupt, and some of their friends are dead . . . where they no longer worry about their own pregnancies but about their daughters.' "

SO IF Fear of Flying represented one giddy high in the first flush of liberation, Parachutes & Kisses shows us their more sobering aftermath. To be candid, it was more thrilling to read about a recognizable, sexually voracious woman who rejects her husband than to read, as we do here, about one whose husband leaves her. But Isadora still has plenty of good times to tell us about. With her survivor mentality, she mourns the death of her marriage by recalling the wonder of the birth of their daughter. She offers some trenchant stories about living alone in a fancy Connecticut house without a man to fix the boiler or negotiate the treacherous driveway in the snow. In the one really hilarious scene in the book, she tells about the horror of inviting a similarly separated man-with-child to spend the weekend. (He brings his revolting son, who hates her daughter; together they manage to invent a new version of coitus interruptus.)

Jong's reports on Life Among the Wasps in Connecticut and Among the Post-Liberation Divorce Crowd are fun to read; the woman has kept her sense of humor, thank goodness. Less successful is her sub- plot about returning to her roots in Russia after the death of her beloved grandfather. But overall, there's a deliberate message here, in between the couplings. And the message is that even women who have it all don't really have it all. "She wanted to come to that lovely moment of inner-directedness where she delighted in her strength without wondering whether a male (or female) audience would be there to give her a standing ovation for it. She had won all the other battles most women never win -- her own profession, her own money, her own autonomy from both father and husband. But in her heart, she still had Daddy installed as censor, judge, arbiter of her achievements. And if she, with all her freedom, was so unfree, what did that bode for other women?"

By the end of Parachutes & Kisses, Isadora has a new adoring male audience, the aforementioned Bean. But she still is not free. I hope Erica Jong plans more sequels; it will be instructive to watch Isadora Wing continue her struggle to grow up while she grows old.