Joan Aiken produced more than a hundred books, including more than a dozen collections of fantasy stories, plays and poems, and modern and historical novels for adults and children. She was a lifelong fan of ghost stories, particularly those of M. R. James, Fitz James O’Brien and Nugent Barker. Some of her books focus on spine-chilling or supernatural events, including The Windscreen Weepers (stories, 1969), The Shadow Guests (novel, 1980), A Whisper in the Night (stories, 1982), and A Creepy Company (stories, 1993, with variant contents in its US and UK editions). She set her adult supernatural novel, The Haunting of Lamb House, at Lamb House in Rye (now a National Trust property). This ghost story recounts in fictional form an alleged haunting experienced by two former residents of the house, Henry James and E. F. Benson, both of whom also wrote ghost stories. Many of Joan Aiken’s most popular books, including the Wolves Chronicles (also known as The Wolves of Willoughby Chase series or the James III series), are set in an elaborate alternative history of Britain in which James II was never deposed in the Glorious Revolution, but supporters of the House of Hanover continually agitate against the monarchy. These books also toy with the geography of London, adding a Canal District among other features. Wolves have invaded the country from Europe via the newly built Channel Tunnel. The novels share a varying cast and a variety of interlinked child protagonists – initially Bonnie Green, but subsequently her itinerant friend Simon, Simon’s intrepid Cockney friend Dido Twite (the heroine of most of the books), Dido’s half-sister Is and Owen Hughes (son of Dido’s Royal Navy ally Captain Hughes).

In a review of Midwinter Nightingale for the School Library Journal, Susan Patron praised the characterisations and the suspenseful plot and noted that “although the titles in the ‘Wolves’ series may be read independently”, readers may want to read the earlier books first. Joan Aiken’s series of children’s books about Arabel and Mortimer were illustrated by Quentin Blake. Others were illustrated by Jan Pieńkowski and Pat Marriott. Pieńkowski won the foremost British award for children’s book illustration, the Greenaway Medal, for The Kingdom Under the Sea and Other Stories (Jonathan Cape, 1971), a collection of “unique fairy tales from Eastern Europe and Russia” retold by Aiken. Joan Aiken participated in the Puffin Book Club’s annual Children’s Literature Summer Camp, run by Colony Holidays, predecessor to ATE Superweeks, along with other popular children’s authors such as Ian Serraillier and Clive King. Aiken’s many novels for adults include several that continue or complement novels by Jane Austen. These include Mansfield Revisited and Jane Fairfax. Joan Aiken died at home at the age of 79. She was survived by her two children.