Christie presents Parker Pyne as having a solid if bland physical presence, one which is characteristically English and somehow vaguely comforting to those around him, though they themselves could not articulate exactly how or why. The character is first described in "The Case of the Middle-aged Wife" as follows:
Somehow or other, the mere sight of Mr. Parker Pyne brought a feeling of reassurance. He was large but not to say fat; he had a bald head of noble proportions, strong glasses, and little twinkling eyes.
In the short stories of Parker Pyne Investigates (1934), Christie repeatedly gives the detective's full name as James Parker Pyne, although in his newspaper advertisements he strictly uses his middle name (rather than his first) for all business purposes.
Confusion over his first name possibly being "Christopher" stems from a later story, "Problem at Pollensa Bay" (1935), wherein Pyne uses the pseudonym as a ruse to obfuscate his identity from fellow British travellers so that he would not be disturbed while on holiday. After multiple failed attempts to enjoy a peaceful vacation unfettered by work, Pyne settles in comfortably at Majorca but, almost immediately, is dismayed to encounter another distressed Englishwoman who may recognise his celebrated name from the newspapers. He had already signed in as "C. Parker Pyne" in the hotel register but, hoping to conceal his profession from this woman, he returns to the book and scribbles over the entry to change it to "Christopher" instead.
Although use of the full name Christopher is plainly intended here as a calligraphic cover-up, it is unclear whether Pyne's earlier notation of "C" (instead of "J" for James) was likewise a flimsy effort at disguise, or whether this was merely an oversight in continuity on Christie's part. Alternately possible, the name change could have been a deliberate alteration by the author, though in that case the reason for it is unexplained.
Only one further Pyne story, "The Regatta Mystery," follows these in the Christie canon, and as it does not touch on the topic of the detective's first name, it sheds no additional light on what the author's intention might have been on the matter.
Parker Pyne is a retired government employee turned philanthropist who considers himself to be a "detective of the heart". The exact nature of his former job and his former position in the British government was never stated but he claimed to have been involved in the gathering of statistics. This leads to the theory that his job was the same as Mycroft Holmes, a human super computer, specialising in omniscience.
This theory carries some weight as the resemblance between Parker Pyne and Mycroft Holmes is hard to deny. Both are heavy set fellows. Both appear to possess superior skills to that of their counterparts (Sherlock Holmes/Hercule Poirot) but they are both nonetheless incapable of performing similar detective work since they are both unwilling to put in the physical effort necessary to bring cases to their conclusions.
While he does occasionally exert himself in the stories where he is on vacation, he on the whole remains a sedentary problem-solver, providing solutions based on seemingly little evidence and trusting his agents to handle any of the practical details. He himself rarely goes to see his clients after their first meeting, although he gets reports on their progress from his hench-people. In fact, Pyne's own lack of drive and faith in his minions' skills can be a severe handicap despite his deductive talents, as it resulted in the failure of his efforts in "The Case of the Discontented Husband", Pyne's only recorded failure.
Parker Pyne is also an uncommon type of detective, who doesn't usually investigate murders or similar crimes, but rather prefers to help his clients to re-encounter happiness. For such, he applies the knowledge he has acquired in 35 years of work in a statistics office, from which he retired, establishing later on his own on 17 Richmond Street, London.
He has a theory that there are five main types of unhappiness and all are logically solvable. His methods are unorthodox and he often employs deception and constructs elaborate charades to fool the suspects and cure unhappiness successfully.
Though he is, apparently, limited to a specific type of investigation, Pyne also has uncommon capabilities for criminal investigation. He works alongside his neurotic assistant Miss Felicity Lemon, novelist Ariadne Oliver, handsome lounge lizard Claude Luttrell and disguise artist Madeline de Sara. Whatever the case is, he always has the aid of his team (outnumbered, but as effective as they are extravagant).
Agatha Christie published a total of 14 short stories featuring Parker Pyne. Of these, the first dozen initially appeared in various US/UK magazines and were later collected into the 1934 anthology Parker Pyne Investigates. The remaining two tales were originally created as vehicles for her most famous sleuth, Belgian detective Hercule Poirot, but Christie reworked these into Pyne cases before their inclusion in the 1939 short story collection The Regatta Mystery and Other Stories.
Within his work, Pyne himself always disclaimed the role of hard-core detective, and his literary domain was usually relegated to light-hearted short stories rather than murder mysteries (excepting two instances where he was inadvertently involved). Christie never featured this character in a full-length novel and, despite her lengthy career, did not return to her Pyne creation after this initial 1930s run.1932 – "The Case of the Discontented Soldier" – Parker Pyne becomes involved in secret maps to buried treasure when helping a major newly returned from abroad.
1932 – "The Case of the Middle-aged Wife" – Pyne helps to save a failing marriage.
1932 – "The Case of the Distressed Lady" – Pyne shows his slippery side when helping an apparently distressed woman.
1932 – "The Case of the Discontented Husband" – Pyne once again becomes embroiled in resolving marital woes.
1932 – "The Case of the City Clerk" – Pyne helps a mild-mannered city clerk find excitement.
1932 – "The Case of the Rich Lady" – Pyne helps a bored, wealthy widow to spend her money, in his own unconventional way.
1933 – "Have You Got Everything You Want?" – Pyne helps an American woman unravel the secret goings-on aboard a train from Paris.
1933 – "The Gate of Baghdad" – A fellow traveller is murdered en route and Pyne is forced to investigate.
1933 – "The House at Shiraz" – Pyne investigates the mystery surrounding an English expatriate living as a recluse in Persia.
1933 – "The Pearl of Price" – Traveling in Jordan, Pyne helps to recover the titular pearl.
1933 – "Death on the Nile" – Pyne is hired by a woman who believes her husband may be poisoning her.
1933 – "The Oracle of Delphi" – Pyne aids in the rescue of a kidnapped child.
1935 – "Problem at Pollensa Bay" – concerns a mother's dislike for her son's fiancée, a dilemma solved by fellow vacationer Pyne.
1936 – "The Regatta Mystery" – Pyne catches a diamond thief during regatta festivities at Dartmouth Harbour.
The Agatha Christie Hour (1982), a series of ten-hour-long dramas produced for Thames TV, London, featured two episodes based on Parker Pyne stories: "The Case of the Middle-aged Wife" and "The Case of the Discontented Soldier", both directed by Michael Simpson. Veteran character actor Maurice Denham played the role of Parker Pyne. Richard Griffiths played Parker Pyne in adaptations for BBC radio.
Pyne's secretary, Miss Lemon, is apparently the same woman who was secretary to Hercule Poirot. Whether she came into Pyne's employ during one of Poirot’s numerous retirements or before she entered his employ is unknown, though she is described as "a young woman" in Parker Pyne's story The Discontented Soldier, but as having grizzled hair in the Poirot novel Hickory Dickory Dock, suggesting that she worked for Pyne before working for Poirot. This, along with the appearance of Ariadne Oliver, suggests that Pyne and Poirot occupy the same fictional universe even though they have never actually met.