Agatha Christie up to the last chapter, then decided who the most unlikely suspect was, after which she would go back and make the necessary changes to "frame" that person. However, John Curran's "Agatha Christie: The Secret Notebooks" describes different working methods for every book in Christie's bibliography, contradicting the claim by Aldiss. Christie's mature novels, from 1940 onwards, often have titles drawn from literature. Four are from Shakespeare: Three are from the Bible: Another six are from other works of literature: In such cases, the original context of the title is usually printed as an epigraph. Similarly, the title of Christie's
Agatha Christie's fictional universe after Agatha Christie died, are included in the lists. Her novels under the pen name Mary Westmacott and her nonfiction books are not covered in this article. One notable example of characters from one novel appearing in another is the novel "The Pale Horse", which features Ariadne Oliver, Major Despard and his wife Rhoda (all had previously appeared on "Cards on the Table") and Mrs Dane Calthrop (from "The Moving Finger"). Outside of stories by Christie herself, adaptations of her works have also featured crossovers: Agatha Christie's fictional universe In Agatha Christie's mystery novels, several characters cross over different sagas,