She is probably best known for two series of fantasy novels: The Magician Trilogy (1986–1989), contemporary stories rooted in Welsh myth, and Children of the Red King (2002–2010), featuring schoolchildren endowed with magical powers.
She currently lives in Wales, sharing her time between writing and helping her husband with a summer art school.
[10] Gwen's first published book as both writer and illustrator was Bear and Bird (Egmont, September 2012).
[15] There are eight books in the series, all first published by Egmont Press in British trade paperback editions with cover art by David Wyatt.
[9] The Snow Spider and its sequels were adapted for television by the screenwriter Julia Jones, as three miniseries that HTV aired 1989 to 1991.
[7] In December 2023, Amazon MGM Studios announced that a film adaptation of the novel, Midnight for Charlie Bone, is in development.