By now you have seen Gloria Vanderbilt on television, her dead-white makeup pasted on that pigeon face, flouncing around in her own designer jeans while her fast friend and favorite dancing partner, Bobby Short, warbles, " . . . because Gloria Vanderbilt bottoms are the tops." Perhaps you've even wondered why this jet-setter, this heiress, this social butterfly with four marriages and her own designer sheets, towels, pillowcases and God knows what else behind her, so often runs the risk of foofdom, persistently grinning like a banshee on amphetamine. What's the story on this woman anyway?

Well, Barbara Goldsmith -- who often sprints in the same kind of fast lane as The Jean Queen -- in her absolutely-not-authorized, semi-biography, "Little Gloria . . . Happy At Last, " gives us some of this to chew on:

Gloria's mother (Gloria Morgan Vanderbilt) comes across as a selfish, wasteful, money-hungry trollop, standing accused, by her own mother no less (Laura Morgan, a nut case if there ever was one) of a lesbian encounter and wanting to murder Little Gloria, and is declared unfit to retain full custody of the child, in favor of Little Gloria's aunt (Gertrude Vanderbilt Whitney) who is said to have had a lesbian relationship of her own, who admits to being a closet bohemian and who, after gaining custody, loses all interest in the child whatsoever, the child of her brother (Reginald Vanderbilt) a gambler, an alcoholic, a "professional gentleman," a man who dissipated almost $25 million in 14 years, whose own mother (Alice Gwynne Vanderbilt) was so diffident she wouldn't give her chauffeur directions to an address she knew -- even after the chauffeur became hopelessly lost -- because she thought it beneath her to speak to the man.

And you wondered why Gloria acts like that.

The feeling in publishing circles is that this book will be one of the hottest books of the summer, 600 pages of society (Vanderbilts, Whitneys, the former Prince of Wales), sex (lesbianism, pornography, affairs with the former Prince of Wales), and scandal (alcoholism, maternal neglect, cover-up of the involvement of the former Prince of Wales).As review in Newsday called it "moth-to-flame reading." A best-selling author, who has written distinguished books of her own, said, admiringly, "I think it's like candy, this kind of book -- it's one of those summer books you will kill for on the beach." And Goldsmith herself, who got "shall we say a six-figure advance," who got $672,000 for the paperback sale, who will get a million-plus movie deal ("I want the movie rights -- Ali MacGraw IS Gloria Vanderbilt," screamed Alan Carr, producer of solid gold scholock like "Grease" and "Can't Stop The Music"). Goldsmith herself admits the fantasy: "To walk down the beach this summer where we live in East Hampton and see everybody reading the book. I even daydream about getting a purple bathing suit to match the book jacket."

But for those of you dying for the latest gossip on Our Gloria, wanting to know if she'll marry Short, if she'll start designing condominiums, if she'll renounce her celebrity and become a nun -- you're out of luck. This book is about "The Matter of Vanderbilt," the 1934 custody trial and events leading to it. Not even 30 pages are devoted to Our Gloria. Only one paragraph deals with her famous bottoms. Barbara Goldsmith -- who says she doesn't even own one pair ("I've been working on this for five straight years and I haven't had time to buy any new clothes") -- could care less.

She hardly even knows that person.

"The most fleeting acquaintance. If we saw each other at a party, we'd have to be introduced."

She hardly even talked to that person.

"I called her in 1977 to interview her for the book. She said she wouldn't be comfortable doing it, that she planned on writing her own book. She told me she'd read my novel and thought I was a brillant writer, and she wished me good luck. The conversation took maybe 15 or 20 minutes."

She hardly even thinks of that person.

"This is not a book about the person. I have very little interest in that person. She might make a nice dinner guest, but can I think of 500 people I'd rather meet. I am obsessed with that child. I sometimes have to remind myself that this woman was Little Gloria Vanderbilt. I can give you 600 pages that will make everything she does today rational or explainable. yPast that I don't know any more than you do.

"People try to tell me more. They say, 'I have to tell you about Gloria, about when she was married to . . .' That's as far as they get. I cut them off. I just don't want to know. I only know what I read in Suzy or on Page Six (the gossip page of The New York Post). I didn't write a biography of Gloria Vanderbilt, I wrote a social history about a time of opulent waste in America that will never come again, where people gave dinner parties with sand on the table and you'd dig for jewels and come up with an emerald. Gloria Vanderbilt herself is the stone I TOSS in the pond. I wanted to follow the CIRCLES."

Speaking of ponds, Little Gloria was baptized in a bucket of White Rock club soda. Members of the family were so excited about the event that they forgot to supply water.

The very first copy was sent to Our Gloria. Although Goldsmith doesn't particularly care about her, she "roots for her." She "admires" her.

"I hope she reads it. I think she will."

Our Gloria, America's heiress, the poor little rich girl of the most scandalous custody trial in history -- give us a break already; she's 56 years old -- is not talking. No way.

Thomas A. Andrews, her attorney -- "and I represent other Vanderbilts and Whitneys also" -- is answering all questions. He hadn't read the book, but he had no reservation about calling it a clip job. "There's nothing new in it. All it is, is a rehash of press clippings and interviews with people who were peripheral to the story. They were hangers-on then. They are hangers-on now. And they're not even good at hanging on." Andrews said he didn't have to read the book "because I have access to the source. This is just an attempt to captialize on Gloria's popularity. Gloria has always maintained that when the real story is to be written, she will write it."

Clip job!

Goldsmith didn't like that.

She heard the words and made a face, grabbed one of the four strands of pearls hanging fashionably loose around her neck and tossed it back.

"That makes me angry," she said in a patrician seethe that some people use to tell a waiter that the vichyssoise is warm. "It's a lie. If it was a clip job, I'd have done it in a year. It was turning a stone into a SOUFFLE that took five years. Five years of research. Seven different countries. If he didn't read the book, how does he know who I talked to? I talked to 300 people. He knows all 300? Every WORD in this book is documented."

Barbara Goldsmith smiled her smile, a smile that, in truth, resembled Gloria's own, that same smile that Goldsmith has called "feral . . . a mask . . . pained." She spoke slowly, accentuating certain words, capitalizing them actually, as if she was writing a screenplay with her voice. She was very expressive, very sincere, very sure, very -- perish the thought -- rehearsed.

"Nothing he says can diminish the importance of 'Little Gloria . . . Happy At Last.' What's new is my VISION of the book, which is unique. The SCOPE of it, the tapestry, the CANVAS is IMMENSE. That trial was a watershed event, a WATERSHED event in American society, and this book is a very IMPORTANT book. It will be on library shelves for years."

She had hoped to keep the publicity tour she was on to a minimum.

She had hoped, "in some small way, the book would speak for itself on merit."

She said, "I'm a writer, not a talker."

There was a publishing party last week in New York. It was held in the apartment of restaurateur Warner LeRoy and attended by such people -- according to Suzy -- as Our Gloria's former schoolmate, Dina Merrill, and her husband, Cliff Robertson, Wilfred Sheed, Tom Wolfe, Geroge Plimpton, Joseph Heller, James Kirkwood and people with direct Vanderbilt ties such as Lelia Hadley, B.H. Friedman (Gertrude Vanderbilt Whitney's biographer) and family member Flora Miller Irving. Many of those in attendance were said to be friends of both Gloria Vanderbilt and Barbara Goldsmith, a chalk daily-double in New York's literary/socialite Cafe Society.

Andrews scoffed.

"The people who went to that party will go anywhere there's a free meal. None of Gloria's close friends were there."

Goldsmith simmered.

"Nonsense.I've had reaction from family members who told me they were impressed with the incredible accuracy of the book. And family members were there. Would a Whitney go anywhere for a free meal?"

But there has been no official family comment yet. Indeed, if the Vanderbilt family commented officially on each new historical dissection, they would hardly have enough time to make enough money to buy even a small country.No, you have to phone around to the fashionable places to get them, and once in a while you get lucky.

"I certainly think the whole matter should be dropped already, and I think the whole family feels that way," said one cousin, begging anonymity.

Another family member, who hadn't yet read the book -- she had it on order -- said that the excerpt in Life magazine made her "depressed and distressed. I thought the exposure was just too terrible. There's no protection, no security against this invasion of priivacy. It should be a crime to write something like this, especially without Gloria's permission. Isn't there a law against it?

Like what?

Invasion of publicity?

How can you embarrass someone who just last week at a fund raiser -- according to Suzy -- made an impromptu speech calling herself "a child of The Depression" and told of driving through The Depression with her Aunt Gertrude in a gray "Rolls-Roy." Poor kid. No, Our Gloria belongs to that special cadre of people including such as Truman Capote, Andy Warhol and Margaret Trudeau, who seems to be beyond embarassment.

Then, after the book came, that same family member -- Louise, wife of George, the nephew of Gertrude -- altered her stance. Reading Goldsmith's theory that Little Gloria was so terrified of being kidnapped and murdered -- like the Lindbergh baby, a child of the same time -- that she lost all distinction between fantasy and reality and suffered trauma, Louise Vinderbilt said, "If exposing this helps other families and other children understand this kind of trauma, it will be very worthwhile."

Barbara Goldsmith, now 49, who was born to some comfort and who was also afraid of being kidnapped as a child, was a profile writer for Women's Home Companion and The New York Herald Tribune, an editor at Harper's Bazaar and New York, and investigative reporter and a novelist, was married to an investment banker and is now (second marriage for each) married to Frank Perry, the film director, living in New York City and East Hampton. You can learn all this from People magazine, which last week put Barbara and Frank in its "Couples" section.From other sources you learn that the couple has had their kitchen photographed for one of those beautiful house magazines, and that they are known to throw big, important parties for big, important people. If that sounds like Cafe Society, Barbara Goldsmith says it isn't.

"How can I be in Cafe Society, when I hardly ever go out to dinner?" she asked.

"I'm very involved in my private life," she said, a private life which People reported includes such friends as Roy Lichtenstein, Larry Rivers, Paula Prentiss, Dick Benjamin, Joan Didion and John Gregory Dunne.

Barbara Goldsmith began this project "just by accident" when she was in a law library researching her novel "Straw Man" and happened to see on the shelves some volumes entitled "The Matter of Vanderbilt." She found out they were not sealed records, as she was originally told, and began to read them. Court transcripts. The real poop.

"Once I started to read, I ABSOLUTELY felt as if I was CATAPULATED back into the year 1934. I knew what they WORE, what they ate for breakfast. I suddenly realized that this was a UNIQUE chink of history. It wasn't Proust -- that was long ago -- and it wasn't yet "In Cold Blood' or 'The Executioner's Song." But those same TECHNIQUES could capture this period. I had a LOCOMOTIVE of a narrative."

She told none of her friends what she was up to. For five years.

She handed in a 150-page research outline to her publisher and got her "shall we say, a six-figure advance." And still she told no one what she was up to.

She says, "Honestly, I didn't think of the money. I was obsessed by the story."

Sex, society and scandal in 600 pages.

Now, suddenly this summer, she's hot.

And what if people say it reads like Liz Smith?

Barbara Goldsmith wasn't smiling.

"No" she said, "it's supposed to come out like Proust."