CYNTHIA PROPPER SETON is the kind of writer readers like to discover for themselves because she is a rare find. She is unique in her witty and compassionate view of the human comedy underlying the recurrent waves of contemporary movements. She is unique, also, in the deft, compressed, almost aphoristic style and the wry, sharp, funny, but always sympathetic tone with which she reveals it to us. She may be, as one of her characters in this new novel says of anothr, a writer who writes for readers with two fixed habits: "One is they don't read fiction, and the other is they don't buy hardbacks." But those who have found her and delight in her books are, I suspect, fast becoming a devoted following, bent on enlisting others.

The biographical note on the book jacket tells us that Cynthia Seton calls herself a feminist, "but a flawed feminist." This seems a halfhearted effort to forestall the rage her heroine, Celia Dupont, may evoke from the doctrinaire, much in the manner of Celia herself who tends to end her serious statements with a laugh "Her laughs were intended to head off somebody else's laugh."

Celia -- wife and mother (of five daughters!), a woman "designed to be good," is 45 as the book opens. "Time and the bearing and rearing of children had changed her from the stringy, nervous, straw-colored girl she had been, to something pink and fleshier, almost voluptuous -- the sort of metamorphosis that goes largely unrecognized by a husband." She is intent on making the final third of her life "a glorious third." Her plan for doing so is appealing but out of step. Celia wants to dedicate her final third to a private program of learning. "No, I want to make the third third of my life the best third -- the worst of times the best of times. I want to become... an educated person. I look around, and there are... almost none." Her decision is fortified by her belief that her world is ending. It was April of 1968, "a false spring in many respects. It was filled with the promise of becoming the nadir of the present cycle of recent history."

"Outside there will be the vulgar racket of the last of civilization barreling over the cliff -- Philip's certain Nixon is going to win," she explains to Peter Jacobs, a middle-aged historian with whose life her own becomes entwined, "and inside there I'll be, a sort of partial recluse, holed up and reading its history and literature -- till the flames reach me. I'm willing to do light housework in exchange.... And then, if by some miracle, this country is restored, regenerated, -- well then, there I'll be, a national resource!"

Celia's world is that of the uppermiddle-class liberals and intellectuals whose moral fervor fueled and funded the civil rights and peace movementts. They exhort department store owners to use black models, make new and interesting friends at McCarthy fundraising rallies and spend Sundays at peace vigils in the Bronx. She and her editor husband Philip seem ideally suited to each other but "were now enduring a tension of considerable stress for them over the most intimate issue of them all: the choice of a Democratic presidential candidate." Actually Philip is also feeling the stress of middle-aged sexual yearnings focused on Lily, a young, vivid, and self-centered feminist writer.

The light irony and rather glancing social criticism implied by the quotations above do not do justice to the underlying seriousness with which the writer perceives our dilemmas and self-deceptions. Her Celia becomes a witness to the plight of those women who, aware of the need for struggle, are nevertheless reluctant to abandon the deepening of being and experience to be found in the family and the succession of the generations. Her placid plan for her personal future becomes complicated by the modern possibility of sexual adventure in mid-life. Her personal response will, perhaps, surprise readers.

It must be noted that, as a novel -- a novel must, after all, tell a story -- this books bogs down a bit in the second part. Perhaps it is because the setting and the characters seem a bit stock. Provence and the Riviera have provided a background for many idylls, middle-aged or otherwise. And the aging, unconventional free spirit (Celia's mother, Agnes) and her friends, the faithful and somewhat bitchy homosexual duo, are familiar figures. Celia and Peter Jacobs seem to fade in their company.

The reader's interest will quicken again aptly enough in the final third of the book. The freshness of the author's insight and irony plays like summer lightning around the final confrontation between Lily and Celia talking about lesbianism and abortion, thus rescuing the dialogue from the prevailing cant. And for this reader, at least, the final chapter, in which the succession of the generations is resumed, affirms -- at least for the moment -- Philip's conclusion that those of us alive today "are an aristocracy, an aristocracy of survivors."