Poirot Investigates is a short story collection written by English author Agatha Christie and first published in the UK by The Bodley Head in March 1924.

She has received three letters, handed to her by a Chinese man, which warn her to return her fabulous diamond jewel, the "Western Star", to where it came from – the left eye of an idol – before the next full moon.

There were rumours that Mr Maltravers was in a difficult financial position and the suggestion has been made that he paid the insurance premiums and then committed suicide for the benefit of his beautiful young wife.

Poirot figures out that this story, told at the dinner table the day before the tragedy, gave Mrs Maltravers the idea of how to kill her husband by making him demonstrate to her how the victim would have put the gun in his mouth and then pulling the trigger.

Inspector Japp tells Poirot that important American naval plans were stolen from that country by an Italian called Luigi Valdarno who managed to pass them to a suspected spy for Japan, Elsa Hardt, before being killed in New York.

That night, when the Robinsons' flat is empty, Poirot and Hastings lie in wait and apprehend another Italian who has come to kill Hardt and her accomplice in revenge for the death of Valdarno.

As Havering goes off with Japp, Hastings speaks with the housekeeper, Mrs Middleton, who tells him she showed a black-bearded man into the house the previous evening who wanted to see Mr Pace.

After Vavasour states that Shaw has just recovered from a bout of bronchitis, Poirot and Hastings travel to Liverpool, where the ship has recently returned from its ocean crossing.

Learning from the stewards that an elderly invalid man occupied the cabin adjacent to Ridgeway's and hardly ever left it, Poirot declares the case solved and sends an explanation to Scotland Yard so the police can arrest the thief.

The card that Poirot had them handle was treated to yield good fingerprints, which he gave to Japp so the latter could confirm the pair's identities as known jewel thieves and make the arrest at the hotel.

During the First World War, Hastings calls on Poirot to discuss a recent assassination attempt targeting David MacAdam, the British Prime Minister.

Two high-ranking government officials arrive with an urgent request for Poirot's assistance in locating MacAdam, who has been kidnapped while travelling to Versailles for a secret peace conference.

His car suddenly turned off the main road and was accosted by a gang of masked men, who shot at MacAdam and grazed his cheek when he put his head out of the window.

Once the group arrives in France, Poirot insists that they should check into a hotel instead of searching for MacAdam; after thinking for five hours, he announces that they must return to England in order to investigate the case properly.

Accompanied by Hastings and the detectives, Poirot enquires at several cottage hospitals to the west of London, then directs them to a house where the police bring out a woman and two men, one of whom he identifies as O'Murphy.

Poirot claims that he can solve the case in one week without leaving his chair, as long as the relevant facts are brought to him, and accepts a five-pound wager from Japp to do so.

Poirot takes interest in the fact that the property has a lake and boathouse, and also in a recent picture of Davenheim that shows him wearing long hair and a full beard and moustache.

Furthermore, a petty criminal named Billy Kellett has been arrested; he had picked up and pawned Davenheim's ring after a man threw it into a ditch, used the money to get drunk, and assaulted an officer.

Several months earlier, under the guise of going abroad on business, he created the identity of Kellett, changed his appearance, and committed a crime that earned him a three-month jail sentence.

He staged the safe break-in, fled with the contents before Lowen arrived in order to set him up, threw his usual clothes into the lake after changing at the boathouse, and got himself arrested as Kellett to avoid police scrutiny.

Poirot and Hastings are in their rooms with a neighbour, Dr Hawker, when the medical man's housekeeper arrives with the message that a client, Count Foscatini, has phoned for the doctor, crying out for help.

Ascanio is quickly arrested, but Poirot states three points of interest: the coffee was very black, the side dish and dessert were relatively untouched, and the curtains were not drawn.

Andrew's will stipulates that Violet may live in his house for one year, during which time she must "prove her wits" in order to inherit his estate; if she fails, it is to be donated to various charitable institutions.

The review in The Times Literary Supplement of 3 April 1924 began with a note of caution but then became more positive: "When in the first of M. Poirot's adventures, we find a famous diamond that has been the eye of a god and a cryptic message that it will be taken from its possessor 'at the full of the moon' we are inclined to grow indignant on behalf of our dear old friend the moonstone.

He did admit that "it is to be feared that some of the evidence [Poirot] collects would fare badly in criminal courts" but concluded, "Miss Christie's new book, in a word, is for the lightest of reading.

Unlike The New York Times, the reviewer favourably compared some of the stories to those of Sherlock Holmes and concluded, "We hope that the partnership [of Poirot, Hastings and Japp] will last long and yield many more narratives as exciting as these.

He is gay, gallant, transparently vain, and the adroitness with which he solves a mystery has more of the manner of the prestidigitator than of the cold-blooded, relentless tracker-down of crime of most detective stories.

He has a Gallic taste for the dramatic, and in The Tragedy of Marsdon Manor he perhaps gives it undue rein, but mainly the eleven stories in the book are agreeably free from the elaborate contrivance which is always rather a defect in such tales.

The Disappearance of Mr Davenheim was presented on television as a thirty-minute play by CBS as an episode in the series General Electric Theater on 1 April 1962 under the title of Hercule Poirot.

[citation needed] These were as follows: The Adventure of the Western Star was adapted by Stuart Landon into a "Mel Brooks-eque" comedic play titled Poirot Investigates!