She attended the elite Ashley Hall, in Charleston, South Carolina, and graduated from Vassar College in Poughkeepsie, New York, in 1955 with a major in Russian. She worked at several publishing houses, writing catalog and flap copy for books until she got up the nerve to become an author in her own right.
In 1958 she married Leonard Ripley, and divorced in 1963 after having two sons. She re-married with John Graham and she had other two sons.
In 1972, Ripley published her first book, Who's that lady in the President's bed? under the pseudonym B.K. Ripley, and followed it up with half a dozen historical novels, including Charleston, The Time Returns and A Love Divine.
In the early 1990 the estate of Margaret Mitchell selected her to pick up the stories of Scarlett O'Hara and Rhett Butler where Mitchell left them in 1936, the year her saga of the Civil War was published. Mitchell died in 1949.
The selection of Ms. Ripley was mired in controversy from the beginning, in part because it was less than clear that Mitchell, who refused to write a sequel herself, would have wanted anyone else to try.
Ms. Ripley made no bones about why she wanted the assignment.
''There are two reasons why I'm doing this book,'' she said in an interview in the reference work Contemporary Authors. ''I can't resist it, and as soon as this is done I will be able to write anything I want to. I really don't know why Scarlett has such appeal. When I began writing the sequel, I had a lot of trouble because Scarlett is not my kind of person. She's virtually illiterate, has no taste, never learns from her mistakes.''
In her review for The New York Times in September 1991, Janet Maslin characterized the book as a ''stunningly uneventful 823-page holding action.''
The Ripley version takes the story from Atlanta to Tara to Charleston to Savannah to Ireland, where Scarlett remarks, ''My stars, this country's positively peppered with castles.''
It engineers at least a temporary reconciliation with Rhett, with Scarlett even cooking breakfast for him, but such touches led many reviewers to say the characters seemed to have mellowed in ways never suggested by the original book.
After a bidding war, Warner Books won the rights to publish the novel for $4.94 million.
Scarlett was a considerable commercial success and sold 8 million copies despite receiving lackluster reviews. It was also adapted into an eight-hour miniseries that aired on CBS in 1994.
''Thanks to Miss Mitchell and Scarlett, right now I can say any damn thing I want to, and people will listen,'' Ms. Ripley told those attending the 1991 Southeastern Booksellers Association convention.
After the publication of Scarlett, Ms. Ripley wrote other novels that drew better reviews, including From Fields of Gold, published by Warner Books in 1994, and A Love Divine, a novel about Joseph of Arimathea, published by Warner Books in 1996.
She died on Jan. 10 at her home in Richmond, Va. She was 70. Her daughter, Elizabeth Lyon Ripley, told The Associated Press that death resulted from unspecified natural causes. Her widower, retired University of Virginia faculty member John Graham, died three and half years later on July 16, 2007.
She is survived by her daughter Elizabeth, another daughter, Merrill Ripley Geier, and a granddaughter, all of Richmond.
Alexandra Ripley's Books on Amazon: Alexandra Ripley