After the release of her Pulitzer Prize-winning Civil War novel,

Gone With the Wind

, author Margaret Mitchell exchanged letters with a fan in Montgomery County, providing a unique glimpse of the book's creation and characters.

Not much is known of the recipient, Mrs. Harold Jennings, not even her first name. But the Wyncote woman's previously unpublished Mitchell letters are now part of an ongoing online auction expected to bring up to $30,000 by its conclusion Thursday.

In the correspondence, Mitchell wrote Jennings that she "had every detail" of the epic novel in her head before setting "a single word on paper."

But she didn't think "about the end of the book and whether or not Rhett came back to his wife."

"You see, I do not know myself," Mitchell wrote. "I honestly never thought about what happened to the characters after the book ended."

She also told Jennings "I do not plan to write a sequel, nor have I any plans for future writing, as I do not like to write."

An author and journalist who published the one novel in her lifetime, Mitchell was overwhelmed by the response to the book, which gained her international fame and also won the National Book Award for Most Distinguished Novel of 1936.

She received piles of mail from fans and exchanged a series of letters with some, including Jennings, during 1936, 1937, and 1938. They became pen pals and Jennings kept the treasured letters in a meticulously kept scrapbook.

"I am going to try to answer some of your questions," Mitchell wrote in 1936 while trying to explain one of the novel's chief characters, Ashley Wilkes. "I do not know if Ashley was the best drawn character in the book but he was certainly the hardest to draw.

"His was a complex nature and difficult to put on paper," she wrote. "No, Melanie never knew about Ashley and Scarlett. God has a way of shielding the pure of heart - at least He did in my book."

The collection of six one-page letters, four signed Margaret Mitchell and two signed Margaret Mitchell Marsh, focused largely on the book's content and the forthcoming film, which would star Clark Gable as Rhett Butler and Vivien Leigh as Scarlett O'Hara.

The items will be sold by RR Auction in Boston during an online auction scheduled to end Thursday, said Bobby Livingston, executive vice president of the auction firm, which has sold about 60 Mitchell letters and signed books since 1994.

"This is the first time this has been on the market," Livingston said of the Mitchell material. "The correspondence builds."

"Mitchell was thrilled that Mrs. Jennings bought a copy of the book," he said, "and other letters are about what happened to the characters."

One piece of correspondence covered Mitchell's personal history and another, the status of the film.

The owner of the Jennings scrapbook, a Dayton, Ohio, woman who wished to be anonymous, said her father's uncle obtained it in the 1950s or '60s from a friend or a garage sale in Philadelphia.

The uncle and his partner moved to Columbus and later died, leaving the Mitchell materials to be discovered by the current owner and her parents when they came over to wrap up the couple's affairs.

"We came across the scrapbook when we were cleaning, and thought it was cool," the Dayton woman said.

Along with the letters was an informational booklet about Mitchell and her book, with a notation on the front; an unsigned 1938 Christmas card with an envelope in Mitchell's hand; and a five-page typed transcript of a July 3, 1936, radio interview, with Mitchell adding her return address on the reverse of the envelope.

But the typewritten letters signed by Mitchell to Jennings are the highlight.

"I am so glad you took the time to write me," Mitchell wrote in 1936. "It was such a lovely letter and I would not have missed it for anything.

"You asked me to tell you about myself," she wrote. ". . . I have always lived in Atlanta and my parents and grandparents lived here too."

In a letter a few weeks later, Mitchell responded to a Jennings query.

"About obtaining a first edition - I hardly know how to advise you," she wrote. "The prices are so foolishly high, and here in Atlanta, it is difficult to find one, but I imagine a secondhand bookshop could find one for you.

"I do not possess a first edition myself," she wrote. "I never dreamed there would be more than one edition, so did not buy any."