William Corlett, after being educated at Fettes College in Edinburgh, trained as an actor at the Royal Academy of Dramatic Art, in London. He soon started writing plays for the theater, including The Gentle Avalanche and Return Ticket, which were performed in London. Many television plays followed, including the award-winning series Barriers, for which he received the Gold Award at the New York International Film and television Festival. His script for the children's series The Paper Lads won him another Writer's Guild Award for Best Children's Writer.
Between 1978 and 1988, William wrote a number of novels for young adults, including the Gate of Eden, The Land Beyond, Return to the Gate, The Dark Side of the Moon, Bloxworth Blue, and The secret Line. He also co-wrote The Question Series, which is a series of six books about world religions. His adaptation of the Jill Paton Walsh novel Torch was filmed by Edinburgh Films during 1990 and earned him another nomination for the Writer's Guild Best Children's Writer of the Year Award. In addition, his adaptation of the Elizabeth Goudge novel The Little White Horse, was shown on BBC in 1994 and won a Silver Award at the New York International Film and TV Festival. William went on to write the highly acclaimed and best-selling Magician's House Quartet, orginally published by the Bodley Head, which recently became a major BBC television series. The Summer of the Haunting, a contemporary ghost story, is his most recent novel for young readers.