Ruth's father, American millionaire Rufus Van Aldin, and his secretary, Major Knighton, persuade Poirot to take on the case.

Eventually, the avaricious Mirelle, who was on the train with Derek—with whom she had been having an affair but, now spurned, is seeking revenge against him—tells Poirot she saw Derek leave Ruth's compartment around the time the murder would have taken place.

[citation needed] (This location also appear in "The Tuesday Night Club", published in December 1927, the first short story to feature Miss Marple.

[10] A murder mystery adventure featuring Bernède's own popular detective, Chantecoq, the story is set in Paris and the plot is completely different, although it seems likely[original research?

[citation needed] The Times Literary Supplement gave a more positive reaction to the book than Christie herself in its issue of 3 May 1928.

After recounting the set-up of the story, the reviewer concluded: "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".

"[12] British crime writer and critic Robert Barnard declared: "Christie's least favourite story, which she struggled with just before and after the disappearance.

The international setting makes for a good varied read, but there is a plethora of sixth-form schoolgirl French and some deleterious influences from the thrillers.

The novel was adapted for television in 2006,[9] a special episode of the series Agatha Christie's Poirot, airing on ITV on 1 January.

[9] Also featured were Roger Lloyd-Pack as Inspector Caux, James D'Arcy as Derek Kettering, Lindsay Duncan as Lady Tamplin, Alice Eve as Lenox and Elliott Gould as Rufus Van Aldin.

They switch train compartments, and when Ruth is bludgeoned to death, making her features unrecognisable, Poirot speculates that the intended victim may have been Katherine.

At the end of the film, the murderer, Major Richard Knighton, commits suicide by having himself run over by an oncoming train, instead of just being arrested by the French police as in the novel.

The television film also shows Lady Tamplin's fourth husband (Corky by name) acquiring a ruby for her.

[citation needed] The Mystery of the Blue Train was released by HarperCollins as a graphic novel on 3 December 2007, adapted and illustrated by Marc Piskic.

[18] The events of 1926 with the death of her mother and her husband's infidelity had left a deep psychological scar on Christie.

[20] Curtain was written at the same time and similarly locked away, but publication of this latter book would not be possible until the end of her writing career, as it recounts the death of Poirot.

[citation needed] The Mystery of the Blue Train was first serialized in the London evening newspaper The Star in thirty-eight un-illustrated instalments from Wednesday 1 February to Thursday 15 March 1928.

– Carlotta and Peter", which, according to Agatha Christie Limited Staff and others, references the "difficult time" in 1926 of her mother's death and her husband's infidelity, and where "O.F.D."

[citation needed] One person who didn't was Charlotte Fisher (born c. 1901 – died 1976), who had been employed by Christie in 1924 as both her own secretary and as a governess to her daughter Rosalind.

[citation needed] Also named in this latter group, and also in the dedication of the book, is Peter, Christie's beloved terrier, who had been purchased for Rosalind in 1924.

"[23] Peter was also the subject of the dedication of Dumb Witness (on the dustjacket of which he is pictured), published in 1937, one year before his death.