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 vault for over thirty years and were released for publication by Christie only at the end of her life, when she realised that she could not write any more novels. These publications came on the heels of the success of the film version of "Murder on the Orient Express" in 1974. Christie became increasingly tired of Poirot, much as Sir Arthur Conan Doyle had grown weary of his character Sherlock Holmes. By the end of the 1930s, Christie wrote in her diary that she was finding Poirot "insufferable", and by the 1960s she felt that he was "an egocentric creep".