The Mists of Avalon
The Mists of Avalon is a novel by Marion Zimmer Bradley that re-tells the King Arthur myth from a feminist point of view. The main character is Morgaine (in the old sources often called Morgan Le Fay), and the book follows her life instead of Arthur's, thus removing the negative stigma attached to the character.
Marion Zimmer Bradley later expanded the book into a series.
The book was Bradley's most successful and was adapted in 2001 by American cable channel TNT into a miniseries directed by Uli Edel.