Jacqueline Onassis, an editor at Viking Press, did a lot of hard work on "In the Russian Style," said her boss. Thomas H. Guinzburg, and that was how she got her name on the cover.

But the cruical factor in selling books nowadays is publicity, he acknowledged. Onassis had proved to Viking's satisfaction that she could do research, select photographs and write captions - but could she get publicity?

Yes, apparently, she could. Bringing to bear her previous experience as the world's greatest human tourist attraction, she accomplished in two hours what other authors attempt with weeks of travel and talk shows.

"This is her publicity tour right here," said Guinzburg yesterday at a small luncheon for what Viking called "The best of the Press," - The New York Daily News had been excluded with the explanation that "Jackie doesn't like The News - in a private dining room of the Carlyle Hotel. (Viking's "best" included The New York Times, The Los Angeles Times, Time magazine, Newsweek, The Washington Post, Associated Press and United Press International).

"It would probably be great business if you stood at Woodward & Lothrop and signed autographs," the Associated Press representiative suggested.

"Oh, I want to," said Onassis, "But he(Guinzburg) won't let me.

There were seven reporters at the luncheon and five people from Viking, not including the author of the book's introductory text, Audrey Kennett, who her colleagues thought might be out of town anyway. Ground rules were that there were to be no photographers, no tape recorders and no questions about anything except the book. Even inquiries about what other books the editor was working on were turned away as irrelevant.

The book, which is coordinated with an exhibit of costumes at the Metropolitan Museum of Art, is a collection of photographs and quotations concerning imperial life in Russia in the 18th and 19th centuries.

As an historian, Onassis focuses on the rich and powerful - their clothes, jewels, estates and lavish parties, and how much everything cost; their marriages and love affairs, with judgments on which were happy and which not.

As a former First Lady, she has been on the receiving end of such scrutiny, and has protested it. The newsstands are full of movie magazines speculating on her luxuries and the state of her happiness, and if they can't use letters and diaries to document these things, as she did, it's not for lack of trying.

Has her point of view changed about the propriety of examing the private lives of public figures?

"These things were public," she said of her sources. Like Catherine the Great's love letters (My marble beauty . . . I belong to you in every possible way")?

"When it's past, it becomes history," she said. "The present is not." And if a later historian uses her letters, "I won't be here to mind."

The ground rules also enabled Onassis to talk of the dilemma of the very rich - "they had so extraordinary and voracious an appetite for pleasure, but didn't know what to do with their time and money" - as if it were only a remote historical problem. Her being very rich herself, and choosing to dress plainly and work, she dismissed as if there had never been a question of anything else."

"After I got out of college, I wanted to write for a newspaper or work for a publishing house, but I did other things. When the time was right, I did this. I would always have liked to. I see my future as staying on as an editor at Viking hopefully. I love the work I do."

Although she had been invited, she said she would not attend the Inauguration, and nobody at Viking had noticed, when they set her official publication date as Jan. 20, that everything else special was happening that day. She wouldn't attend, she said, "because I have work here."

There was a respectful tone to the luncheon with reporters congratulating Jacqueline Kennedy Onassis on her claim to have passed virtually unnoticed in Russia, and everybody laughing loudly at simple pleasantries. The publicity people from Viking, who had expressed some anxiety beforehand at the occasion's "not being too commercial," pronounced themselves satisfied when it was over. At that point several reporters were besieging her for autographs.

Onassis talked almostly about how the book had come about. She had gotten the idea from new friend Dianna Vreeland, who organized the Metropolitan show, and had worked with book designer Bryan Holme, to whom she gave much credit.

They had allowed the scope of the book to be decided by what the Russians wanted and the items Vreeland had selected. Onassis said she didn't know why only upper-class clothes were included, but guessed that the garments of the poor were "just not very interesting," or had been "so worn, slept in and worn out" that there were no examples remaining.

She said she had spent a week in Russia in June, and had met with no officials except those at museums. "I went with Thomas Hoving, the Metropolitan director," she said, adding with admiration that "for him, going to Russia is like taking the shuttle." It had been her first trip there.

And she talked with great enthusiasm about editing, mentioning particularly such copy-editing tasks as deciding whether to use the spelling of "czar" or "tsar" and how pictures were spread out on the floor when layouts were being debated. She made it sound like the highlight of her life. "Well," she said laughing, "in decibels, I enjoyed it a lot, but I've never done another book."

She has gotten to love the period and will continue to read about it, she said, but apparently without even so slight a personal interest as the desire to try on one of the dresses she admired. "Oh, wouldn't you rather wear blue jeans?" she asked. she was, in fact, wearing a black turtleneck sweater and pants.

But perhaps there was a point of identity in the admiration she expressed for the portrait of a woman serf who became a singer and married her fabulously landowner. "Think how everyone must have gossiped about her," Onassis mused. "But she looked as if she could handle it."