Marion Eleanor Zimmer Bradley was an American author renowned for her work in fantasy, historical fantasy, science fiction, and science fantasy novels. She is best known for the Arthurian fiction novel The Mists of Avalon and the Darkover series. Bradley was noted for the feminist perspective in her writing.

Bradley began writing at the age of 17 and graduated with a Bachelor of Arts degree from Hardin-Simmons University. In 1966, she co-founded the Society for Creative Anachronism and served as the editor of the long-running Sword and Sorceress anthology series. In 2000, she was posthumously awarded the World Fantasy Award for lifetime achievement.

Although Bradley remained popular during her lifetime, her reputation was posthumously marred when, in 2014, her daughter reported allegations of sexual abuse, including assistance in the abusive acts of her second husband, convicted child abuser Walter Breen. These allegations have led many science fiction authors to publicly condemn Bradley.

During her career, Bradley wrote under pseudonyms such as Morgan Ives, Miriam Gardner, John Dexter, and Lee Chapman, among others, and produced works outside her typical speculative fiction genre, including gay and lesbian pulp fiction novels.

Bradley was born on a farm in Albany, New York, during the Great Depression. She died in Berkeley in 1999 after years of declining health. She was married twice, first to Robert Alden Bradley and then to Walter H. Breen, from whom she separated in 1979 but remained married until 1990.