David Llewellyn is a Welsh novelist and script writer. His novels include Eleven; Trace Memory, a spin-off from the BBC drama series Torchwood; and Everything Is Sinister. He has also written two novels for the Doctor Who New Series Adventures: The Taking of Chelsea 426, featuring the Tenth Doctor, and Night of the Humans, featuring the Eleventh Doctor and Amy Pond. In addition to writing novels, Llewellyn wrote the Bernice Summerfield audio play Paradise Frost and the Dark Shadows audio drama The Last Stop for Big Finish Productions.