The rumor was that Emma had been married once. To a congressman. And more, that she had killed him, on assignment for the CIA.

"You always did put your work first," Owen told her, chuckling, the first time he heard the story.

Emma had only shrugged and said, "I spoke to him twice, but he was engrossed in his Whip Memoranda. If he'd only looked up, I might not have done it." Then she had smiled, teasing. -- From "Falseface" by Marilyn Sharp

The nice blond woman on the campaign platform plays the proper congressional wife as she stands in for her husband, the candidate Rep. Philip Sharp (D-Ind.).

Beneath that demure look, she's plotting to hold four congressmen hostage, stockpile hazardous materials under the Lincoln Memorial, kidnap the president's daughter, sabotage an international peace meeting, and give chicken pox to a master spy.

In her not-so-secret life, Marilyn Kay Augburn Sharp writes best-selling suspense novels. Her third, "Falseface" (Richard Marek/St. Martin's Press) is just in the bookshops and the paperback rights are already sold.

She is the perfect campaigner, the perfect talk show author: gregarious, natural and comfortable with people, including strangers. Her voice is full and low, as she writes in "Falseface" of her new spy, Emma Thatcher:

The deep voice, Emma claimed, wasn't a gift of nature as much as experience, the result of some number of years lived in Washington. ('The only way to be heard,' she said, 'in a town where so much talking goes on, is to pitch your voice at a level that's barely audible.')

But Sharp speaks loud and clear on the conflicts between novelist and politician.

"It's insanity to have a new book and an election in the family at the same time," she says. "I had always sworn I wouldn't promote the book and campaign for Phil at the same time."

Not long ago, Sharp was in Muncie, Ind., campaigning for her husband with Robert Redford (who shares the congressman's concerns for the environment). Sharp himself had to cancel out because of a House session. About the same time, three or four Indiana television stations turned down interviews with Marilyn Sharp about "Falseface" because of equal-time considerations.

So, until after the election, she promotes her book in other states. She's good at both campaigning and promoting, not surprising since her previous work experience includes promoting Barbra Streisand and Ringling Bros. and Barnum & Bailey Circus.

Still, she doesn't keep the two lives that separate. "We do live together. I don't mind talking about living with a congressman, it's a big part of my life.

"What I dislike is the assumption from the minute you come here that no matter who you are, what you have done, or what you plan to do, that you will take care of everything because he is so busy.

"When you come here as a congressman's wife, the lines are drawn. The congressmen go into their orientation on how Congress works. The wives are shuffled off to be told how to find houses, where to buy oriental rugs and arrange catering services."

Recently, the woman arranging orientation told Sharp that the congressional leadership would talk to the wives next year -- "thinking I would be thrilled at the acknowledgment of some serious purpose here. I said, 'I'll think you'll be doing the right thing when you get the men to come to the house-hunting session.' "

Thinking back 3 1/2 books, she can pinpoint the time she decided to try to sell her novel.

"They were showing congressional wives through the Pentagon and showed us the floor plan of the airborne command airplane. The man doing the briefing said we'd enjoy knowing about the galley because it's a kitchen. And I thought to myself, 'I must make a life for myself here.' "

Which leads to the question: When she's seated at a dinner table next to the vice president, as she was during the Carter administration, which is she, the political wife or the novelist?

"When we first came to Washington, we saw people who had played a role so long, they had forgotten who they were," she says. "I'm learning to be honest and me. I don't want the traditional life with people telling me what I can't do. I don't want to condemn people who want the traditional role, but it would be phony for me. In the beginning I did feel the need to pretend I was someone else. But I don't any more."

The next day, in the Crestwood neighborhood of Northwest Washington, she showed her "safe house," (as they call a spy's hideaway in the business), a 1920s Tudor-style house, mansion enough to accommodate any number of secret tunnels and lost treasure rooms. The large living room has elaborate plasterwork and the Steinway studio grand piano she bought as a birthday present for her husband on part of the profits from "Sunflower," her first book. The dining room is full of Arts and Crafts Movement antiques from Indiana. They bought the house four years ago, after her second book, "Masterstroke."

The Sharps have two young sons, Jeremy, 8, and Justin, 3, born between books and campaigns. Phil Sharp says that every family vacation, even to Disneyland, gives her ideas. The background for "Falseface" came from a vacation with her husband and Jeremy to the Yucatan and Uxmal.

She's just back now from her first solo trip since they've been married -- a month in Russia, doing research for her fourth novel. Phil Sharp took charge, suppressing the fact until she returned that both boys had chicken pox -- in imitation of the book already at the publishers.

Sharp, on this day, led the way to the top floor of her home where murder, mayhem and mystery are committed (at least to paper) in the sort of space that every writer would like to have. A Lenin poster urges her on. Books, alphabetized, including Russian folklore and her own books translated into Japanese, line the under-the-eaves. A big sofa serves as a place to read Tolstoy (excused as research for the new book), or, as Sharp admits, sleeping when the muse fails.

She hints about the book she won't write. "I have an idea for a story that would be a blockbuster but it would give someone an idea of how to do something nasty. I won't write it."

Where does her knowledge of spying come from?

Her husband is, of course, in on certain briefings.

"But he would not tell me things. I wouldn't want him to. I'm not out to reveal the secrets of the United States. I think it's illegal anyway. I wouldn't want to know things I'm not allowed to use," she says.

She does remember getting the idea for laser beam weapons from her husband. "He didn't know that much about them, just something or other listed in an appropriations bill at that stage." She went to the Library of Congress, studied up on laser weapons and finished her book before Reagan began to talk about "Star Wars" weapons.

But if her husband doesn't tell her state secrets, he repays her campaign help in another way. "Every night he reads out loud what I've done in the day, so I can hear how it sounds. He offers suggestions. He's especially good about helping me keep my characters in character."

"Well," says the congressman, "There was the time when I said, 'You can't have your spy speak so disrespectfully to the president.' And shortly after, the Nixon tapes came out, and I had to admit I was wrong." One time the congressman was sent into the men's room of the White House to describe it so she could murder someone there. But his help has also been in ways less incriminating.

"Phil helped me work through my Indiana training and inhibitions as the perfect lady. I had to realize perfect ladies don't write spy novels. One time, he complained the president in my story wasn't acting tough enough. So he went stomping around the room, acting it out. I got some lines from that one. It changed the place where my mind was. It was a turning point that brought me through an inhibition that hasn't bothered me since."

Though she claims no firsthand knowledge of fistfights and murders, she manages her way through the minimum violence necessary in her novel. On the other hand, though she says she has less against sex than violence, those midwestern inhibitions, or the thought of her mother and husband "and the librarian in Muncie" reading her work, must still bother her. For she neither writes steamy sex scenes nor uses foul language.

Marilyn Sharp doesn't say she won't ever write a sex scene. "Maybe I'll come to a point where it'll have to happen." Richard Owen and Emma Thatcher, her current hero and heroine, she says, may be in love with each other, but they aren't the sort of people to talk about what they do with each other.

She denies that Owen is a rival for Phil Sharp, even though she knows some writers, especially women writers with male heroes, such as Dorothy Sayers and her character Lord Peter Wimsey, have been accused of falling in love with their creation.

Her husband, she says, "puts up with my make-believe people. I'm as crazy as any other author; I love and hate them."

Rep. Sharp says, "I used to tease her about living in a fantasy world, and she looked back at me and said, 'and Congress isn't?' "