(Fictitious character) Hercule Poirot was Agatha Christie's most celebrated characters, although she became a bit tired of him. He appeared in 33 novels, one play (Black Coffee), and more than 50 short stories published between 1920 and 1975.
Poirot is a native French-speaking Belgian; he was a policeman who fled to Britain during World War I and set up as a private investigator. He sometimes worked for the British government on confidential matters. Even after his retirement, he would either pulled into cases either by request from the government or the police, or by happenstance.
Poirot was extremely fastidious, self-satisfied for the most part, and proud of his "little grey cells." He left most forensic work to the police, and solved his cases through ratiocination and his understanding of human nature. Captain Arthur Hastings described him:
"He was hardly more than five feet four inches but carried himself with great dignity. His head was exactly the shape of an egg, and he always perched it a little on one side. His moustache was very stiff and military. Even if everything on his face was covered, the tips of moustache and the pink-tipped nose would be visible.
The neatness of his attire was almost incredible; I believe a speck of dust would have caused him more pain than a bullet wound. Yet this quaint dandified little man who, I was sorry to see, now limped badly, had been in his time one of the most celebrated members of the Belgian police."
In the earlier, in the manner of Sherlock Holmes, he had the bungling associate Captain Hastings and the foil Inspector James Japp. Later, Hastings moved to South America and only occasionally appeared in stories when he was visiting England. Japp is often replaced by other police officers. His is friends with Ariadne Oliver, the mystery novelist, and employed the hyper-efficient Miss Felicity Lemon and a manservant, George. [Hercule Poirot in Wikipedia