Mary Mead, which would later be the home of Agatha Christie's detective Miss Marple the first appearance of the minor recurring character, Mr Goby, who would also appear in After the Funeral and Third Girland the first appearance of Poirot's valet, George.

The novel also contains a number of firsts: there is a reference to the fictional village of St. The Times Literary Supplement said, 'The reader will not be disappointed when the distinguished Belgian on psychological grounds builds up inferences almost out of the air, supports them by a masterly array of negative evidence and lands his fish to the surprise of everyone'. The story itself, even though derived from the 1923 Poirot short story The Plymouth Express, did not come easily to her and she referred to this novel in her autobiography stating that she 'always hated it'. stood for Order of the Faithful Dogs and both Carlotta, hired by Christie as a secretary and Rosalind's governess, and Peter, Rosalind's much loved dog were in that camp as opposed to the Order of the Faithless Rats who had turned away from her.

Carlotta and Peter' also references this difficult time. The dedication 'To the two distinguished members of the O.F.D. Now separated from Archie and in need of funds, she turned back to writing. The events of 1926 with the death of her mother and her husband's infidelity had left a deep psychological scar on Christie. The writing of this book (part of which took place on the Canary Islands in early 1927) was an ordeal for Agatha Christie.

Murder on the blue train