They've dueled in the gossip columns. They're preparing to fight it out in divorce court. And soon they'll be competing in bookstores across the land: Donald the autobiographer vs. Ivana the novelist.

In a move that could go a long way toward making her financially independent of her husband, Ivana Trump is planning to write at least one novel, and probably more. According to the Trumps' prenuptial agreement, Ivana is due in the neighborhood of $20 million -- money she's unlikely to see from her husband in his current debilitated financial condition.

Ivana's representative, the William Morris Agency, is taking her to the international book fair in Frankfurt next week, where there is expected to be a high degree of interest among foreign publishers.

There is no deal yet with an American publisher, although one is anticipated as early as this week. Ivana, who like everyone else involved couldn't be reached for comment yesterday, is meeting this week with potential co-writers and will decide on one soon.

"She's sought after by people around the globe for all sorts of different business activities," one publishing source said yesterday. "Publishing is an area that's always fascinated her, so she's simply decided to become an author."

These days, an increasing number of celebrities are doing the same. Carrie Fisher, Margaret Truman, Roxanne Pulitzer, Kirk Douglas and Joan Collins are recent examples of those best known for other activities (in Pulitzer's case, nothing more than a messy divorce) who have converted to fiction, sometimes with a little help from their friends.

Can the world bear two writing Trumps? At the American Booksellers Association convention in June, The Donald spoke enthusiastically about writing a third book -- especially, he said, if his publisher, S.I. Newhouse, pays him some "real money."

Long before then, the verdict will be in on the second tome, which was published last month by Random House on an accelerated schedule. In its third week on the chart, "Surviving at the Top" fell from No. 1 to No. 10 on the New York Times bestseller list -- a dizzying drop that seemed to confirm the reviewers' verdict that everyone had had enough.

The next week, though, the book rebounded to No. 1; this Sunday, it will be No. 6. "It's not going to be a monster," commented one source, "but it's certainly not in the toilet."