American writer who published over thirty works of science fiction and fantasy and is best known for novels such as A Funeral for the Eyes of Fire, Stolen Faces, Transfigurations and Under Heaven's Bridge. His later works include No Enemy but Time, Ancient of Days and Unicorn Mountain.
After graduating from the University of Georgia, he worked as a freelance writer and a substitute teacher.
He was a two-time recipient of the Nebula Award: The Quickening and No Enemy But Time, both of which won the prestigious honor.
He married Jeri Ellis Whitaker in 1969.
He wrote an introduction to a book by Mary Shelley.