Douglas, who cited fellow Mississippi native William Faulkner as a literary influence, was the pen name of Josephine Ayres Haxton; she said she took a pseudonym to guard the privacy of her family.
Douglas' Mississippi-set work dealt candidly with race relations, families and the role of women.
She grew up in Hope, Ark., and Alexandria, La., and spent summers with her grandparents in Natchez, Miss., where the family's roots reached back generations. She graduated from the University of Mississippi in 1942. She wrote 11 books, including six novels and several collections of short stories and essays.
"Apostles of Light" is a complex novel about the mistreatment of residents at a home for the elderly in fictional Homochitto, Miss., the town in many of her works.
"If you don't have conflict, you don't have fiction," Douglas said in a 2005 interview about race relations and other forces that helped shape literature.
In a 1980 oral history with the Mississippi Department of Archives and History, Douglas said she was influenced by the "overwhelming hypnotic style" of Faulkner, who was living and writing in Oxford when she was a student there at the University of Mississippi.
She said she met him once when she was a student and a couple of times years later, but didn't know him well.
Her 1979 novel, "The Rock Cried Out," is about a young Mississippi man whose cousin was killed during the Freedom Summer of 1964, a pivotal time for the civil rights movement in the Deep South state.
Some of her other works were "A Family's Affairs" and "Can't Quit You, Baby." Douglas won a lifetime achievement award in 2008 from the Mississippi Institute of Arts and Letters.
Cynthia Shearer, a novelist who is a writing consultant at Texas Christian University, said when she did her first public reading of her own writing in the 1980s, Douglas was in the audience in Oxford.
"She didn't know me from Adam, but she beamed at me the whole time, telegraphing bravery to me," Shearer recalled.
Shearer, author of the novels "The Wonder Book of the Air" and "The Celestial Jukebox," said Douglas was quiet and unassuming.
"I saw her sitting by herself at a writer's conference one time after I'd published my first novel, and I took my little glass of white wine over to sit with her," Shearer said. "She held up her glass of bourbon instructionally, and then eyed my white wine sardonically, and said, 'You got to do better than that.' "
Douglas was writer-in-residence at the University of Mississippi from 1979 to 1983. One of her creative writing students was Larry Brown, an Oxford firefighter who later wrote "Big Bad Love" and other gritty novels set in the South. Brown died in 2004.