Columinst William Safire is reportedly about to clinch the sale of his next book, a "saga novel" about Abraham Lincoln.

"We're in the process of negotiating the last fine point of the contract," Doubleday associate editor Blair Brown said yesterday. Safire is expected to sign the final papers some time in the next few weeks.

Doubleday plans to publish what is expected to be a 420-page book three years from now, according to Brown. The hardcover book deal reportedly runs into six figures. "Safire is one of our better writers," said Brown. "He can command a nice price."

Safire -- who said yesterday that he will continue to spend "99 percent of his time working as a New York Times columinist -- is already writing and researching the project. He will spend much of his free time -- particularly early mornings -- working on the book.

"It's a historical novel," Safire said, and "beyond that, I'm not ready to talk about it. People who talk about novels seldom write them." He would not confirm details of the book project.

Safire, a former Nixon speechwriter and a 1978 Pulitzer Prize-winner for commentaries on Bert Lance, is the author of "Safire's Political Dictionary" and the novel "Full Disclosure," with in early 1977 set a paperback auction record of $1.375 million.

Brown described the book as "a refreshing look at American history by an important writer -- a change from fabricating thoughts to breathing life into what historical knowledge there is of Abraham Lincoln."

The book will be "based on historical fact and cover the whole of Lincoln's life in the traditional Safire vein," Brown said.

Doubleday approached Safire about the idea of doing a book on Lincoln, according to Brown.

"Safire has done a great deal of reasearch," Brown explained. "He will look at Lincoln's follies, weaknesses, loves, his attacks on the press.

"He wants to show how Lincoln's personal life weighed on his presidency. He wants to ask, what if Lincoln were president now? We didn't acknowledge that Lincoln was great -- before he was assassinated. Would we now? I think the American people are ready to educate themselves about the American presidency."