No, Geraldine Ferraro said, she hadn't expected to come back to San Francisco quite like this.

She expected Secret Service agents, at least.

"I came here in July as a vice presidential candidate," Ferraro said, gazing out at the people who had filled the great ballroom to hear her speak. "And now I'm back here as an author. Author. It has such a nice ring to it."

In the midst of the American Booksellers Association convention, wedged between the fancy Random House dinner and the Jackie Collins party and the Mother Jones Magazine party and the reception for the forthcoming "The History of American Bandstand," surrounded by publishers and bookstore owners and whispered stories about Norman Mailer and the Lee Iacocca book and the best of last year's children's book line . . . here comes Geraldine Ferraro, book author, sort of.

"Ferraro," the book is called. "My Story." You'll be seeing it, with Ferraro smiling out at you from an elegant off-white armchair, in late October, published by Bantam Books. Ferraro is not literally the author; the nearly completed autobiography is being written "with" former Newsweek editor Linda Bird Franke, who worked on Rosalynn Carter's autobiography, and as Ferraro appeared at the convention today to make what the publicists are calling her "public debut as an author," she was quick to thank Franke for being not only skilled but versatile:

"She's a fabulous writer," Ferraro said, "and when I read the book she's done on Rosalynn Carter, I called Linda up and I said, 'Tell me, how did you make it sound so much like Rosalynn?' "

Ferraro went into a syrupy southern accent, which for her is no mean feat. "She said, 'Wayull, Gerry, ah tahped with a suhthern accent.' And I said, 'What are you going to do for me?' She said, 'I'm going to write with a Queens accent -- real fast.' "

The voice here was conversational, low-key, real fast, the same voice that moved so many crusty political women to tears last fall. She still looked terrific, grabbing the podium with arms outstretched as though she or it might take off at any moment, and she told stories -- amusing stories: being whisked off to Minnesota in unmarked cars while her selection as Walter Mondale's running mate was still secret. "I knew that we were making history, and here I was acting like I was in a James Bond movie," she said.

She told debate stories. "Let me say once and for all, now, publicly -- I agree I should have kept my head up more," Ferraro said. She said she alarmed her staff by finally announcing how she intended to greet George Bush -- "I said what I was going to do was take his hand, grab it hard, and kiss him smack on the lips," Ferraro said. "They were not amused."

She got just slightly wicked: "Did you see how George Bush behaved?" she asked. "Did you notice how he was serious one minute and then giddy the next? Happy one minute and then sad the next? Kind of up and then down? You know, those mood swings -- " wild applause and laughter, and Ferraro smiled broadly. "You've really got to worry about putting a man in a job like that."

Mostly, though, Ferraro talked about women, the political women and the women who had never felt passionate about anything political until Walter Mondale really did choose Geraldine Ferraro as candidate for the American vice presidency. "Everywhere I went, people would yell for me to 'Go for it, Gerry' -- particularly the women," she said. "They say that in this city the women walked around for four days smiling."

She talked about the woman who listened to Ferraro accepting the nomination and then ran to tell her own twins what had happened; the twins were 4 years old. She talked about the Canadian woman who asked for Ferraro's signature for her 9-year-old daughter -- "She's going to be the first female prime minister," Ferraro said the woman told her. She talked about the woman who wrote of having wept as she looked at the Time magazine with Ferraro's picture on the cover -- "tears of joy," the woman wrote, "of saying, 'At last I don't have to feel second class any more.' "

How does running for national office compare with producing a full-length book? "I didn't know that writing the book would be so terribly draining," Ferraro said. "After the campaign was fought last year, I didn't think anything would ever be so hard again . . . I didn't realize I'd actually relive the feelings of the campaign, and that some of them would hurt just as much, and some of them would hurt even more."

Since last December, Ferraro said, she and Franke have spent four to five hours a day rehashing every campaign detail, examining newspaper clippings, listening to tapes, rereading diaries and speeches. Here were the rawest moments all over again, Ferraro said: the bitter fight with the Catholic hierarchy over her position on abortion, and the relentless public curiosity about her family, particularly the personal finances of her husband John Zaccaro, who pleaded guilty in January to real estate fraud charges.

"I tell people, if God had sat me down and said, 'Hey, Ger, let's take a look at the VCR and see the next six months,' " Ferraro said, "I would have said, 'Hey, God, could you pick Dianne?' "

Dianne Feinstein, the mayor of San Francisco, came close enough to the vice presidency that, as Ferraro tells it, when a Mondale aide made the last-minute phone call to find out who the pick had been, his question was, "Is it the blond or the brunette?" It was the blond, of course, and Ferraro said, both in her speech and the brief news conference afterward, that as trying as the whole experience was, there is no real regret about it in her book.

"It is not a whining book -- let me just tell you that. It is an up book," she said. "Whatever else happened in 1984, I will never regret the campaign. It was a gain not only for women -- it was a plus for the country . . . I think what it means for all of us is that Men Only sign has been removed from the doors of the White House."

Is Ferraro courting trouble by releasing both her celebrated Pepsi commercial and a well-publicized autobiography within months of each other? "I don't think so," Ferraro said. She insisted that women love the Pepsi ad, that she wanted to include in it a message for the homemakers who had said the fervor over her candidacy made them feel slighted. "It says two things -- it says women can be whatever they want to be . . . but also, it talks about motherhood as being a very important career choice."

And since she comes from a state where both governor and mayor have recently released autobiographies -- New York City Mayor Ed Koch's autobiography is now a musical, she observed with a grin -- Ferraro is not particularly worried about looking tacky because her picture is about to sweep America on a book jacket. She wanted to point out also that even though former Senate majority leader Howard Baker receives no pay for his endorsement of USA Today, he does sit on the board of Gannett Co., which publishes newspapers (including USA Today) that may make presidential endorsements. "I have a little more problem with that than I have with Pepsi," she said. "I don't think Pepsi's going to endorse me if I ever decide to run for the presidency."