Gillian Cross was born in London in 1945 and studied at Somerville College, Oxford and the University of Sussex.
She is the author of several children's books, including the popular 'Demon Headmaster' stories, comprising of: The Demon Headmaster (1982); The Prime Minister's Brain, later republished as The Demon Headmaster and the Prime Minister's Brain (1985); Hunky Parker is Watching You (1994), later republished as The Revenge of the Demon Headmaster (1994); The Demon Headmaster Strikes Again (1996); The Demon Headmaster Takes Over (1997); and Facing The Demon Headmaster (2002). These books were made into a successful BBC television series, and a musical, which first went on tour in 1998.
Her recent books The Dark Ground (2003), The Black Room (2005), and The Nightmare Game (2006), form The Lost trilogy, a fantasy adventure series. She has also published a picture book for younger children, Brother Aelred's Feet (2007). Her latest books are Where I Belong (2007) and After Tomorrow (2013).
Gillian enjoys orienteering and playing the piano. She has had quite a few informal jobs such as:
For eight years, she was a member of the committee which advises government ministers about public libraries. She always used libraries a lot and thinks that it is very important that public libraries should continue to be free and open to everyone.