Warner Books bid nearly $5 million last week to win the rights to publish a sequel to "Gone With the Wind" authorized by the estate of Margaret Mitchell, a spokesman for the publisher said.

Warner spokeswoman Ellen Herrick said the company agreed to pay $4.94 million for the hardcover and paperback rights to the as yet untitled novel to be written by Alexandra Ripley.The projected publication date will be in 1990. Herrick said the book is expected to be 700 pages long and will begin at the funeral of Melanie Wilkes.

Ripley, 54, a native of Charleston, S.C., must deliver her manuscript in 18 months. Mitchell took 10 years to write "Gone with the Wind," which was made into an equally famous movie in 1939, starring Vivien Leigh and Clark Gable.

Ripley, a self-described author of "big, fat, serious historicals," is the author of "Charleston," "Leaving Charleston," "New Orleans Legacy" and "The Time Returns."

One of 12 writers considered for the project, Ripley actually was asked to write the sequel two years ago, Life reports, because William Morris agent Robert Gottlieb was convinced she "had the skill to bring the post-Civil War era and the formidable Scarlett back to life."

Ripley says her task will not be easy.

"The book will never be mine," she told Life. "It's a foster mother kind of thing. I am trying to prepare myself for a universal hatred of what I'm going to do. Yes, Margaret Mitchell writes better than I do but she's dead."

Mitchell, who opposed a sequel to "Gone With the Wind," was killed by a taxi in Atlanta in 1949.

Ripley said her writing style will differ somewhat from that of Mitchell, who shocked the world with Rhett Butler's exit line, "Frankly, my dear, I don't give a damn."

She plans to handle sex more openly, though not graphically, and avoid Mitchell's use of a thick slave dialect because "black people find it demeaning," Ripley said.

"My hand just won't write `fiddle-dee-dee,"' she said. "But I figure in my 1,000-page book I'll have to give them at least three and throw in `God's nightgown!' `Great balls of fire!" and `As God is my witness!' "

Ripley hints that her sequel likely will find Rhett Butler headed for Charleston after he leaves Scarlett for the last time.

"Scarlett hated Charleston," she said.

Ripley said she has not decided how the book will end or whether Scarlett and Rhett will live happily ever after.

"Well, they could live unhappily ever after," she said.