Agatha Christie had a very distinctive style of storytelling. By viewing all of her stories a notable set of characters emerges that Christie tends to use over and over again. These are not identified by name, but instead tend to be of the same type. By mixing and matching from among the stable, a new cast of characters is assembled for each story. As an example, the Housekeeper is a prominent figure that appears often in Christie murder mysteries. This "type" is usually an older woman who plays a prominent role in a early household, often developing a close relationship with some of the children. This makes her a very versatile character who often sees events from a different perspective, but is a figure who isn't related to the principals.
The other novel innovation is that they character types can play different roles, depending on the needs of the story. They can be heroic, supportive, corrupt, evil, each in turn as the story demands. To return to our example, The Housekeeper can be a totally supportive caretaker of the abandoned child, when the mother's career takes her away from the family. Or, she could be an abusive tyrant who oppressed the lonely child while the mother was away. Or she could be the real mother of the infant, who couldn't afford to raise it and so gave it to the wealthy family to adopt. Three totally different characters when written, but sharing the same basic Type in the drama.
The same "Type" of character can take on different forms, while remaining essentially the same. A character can be reversed and play against type, so that the doctor in one story might be portrayed as being incompetent, instead of highly skilled. Or as neurotic instead of reassuring and stable. Doctors are usually highly moral and sympathetic, but can be reversed to be untrustworthy and out for their own personal glory at the expense of their patients.
1. The Doctor. This man is a promising/ successful doctor but with a hint that something happened in his past that cast a shadow on his present situation. Typically intelligent, sympathetic, good in a crisis, with a developed sense of professional ethics. Can also appear as The Nurse.
One version of the doctor is the Harley Street Specialist, whom one references when looking for obscure diseases and maladies, and particularly when one is looking for a secret illness that is likely terminal.
2. The Energetic Young Woman. She has history that the story will explore, but enjoys current success, possibly financially or professionally. She is often the initial instigator of the inciting action of the plot. Her past is catching up with her, however, in one way or another.
3. The Cloud-headed Girl. This is often a female figure who is portrayed as slightly odd or eccentric. Usually the result of an incident in her childhood, or her odd parents, but she sees the world in a different way and those around her view her as a kind of oddity. She may legitimately suffer from mental illness, or may be the only person who truly sees reality for what it is.
4. The Temptrix. This woman is motivated by using her feminine wiles to steal another woman's husband, their achievements, their fame, their family, their property. Could be rival sisters, or schoolmates. She is a master manipulator and is typically utterly devoid of any scruples. While amoral, she isn't always the main evil of the story.
5. The Young Scientist. A botanist, a photographer, a young engineer. Typically a young man who is technically gifted but socially awkward. May love hopelessly from afar. Used as a resource to supply any obscure poisons, technical gadgets, top secret plans that the plot may require.
6. The Housekeeper. Sometimes Russian or a Gypsy, or French; and if so her spoken English is not fluent. Often devoted to the Lady of the house, or to the neglected children. Fiercely loyal to someone, but from her position and perspective in the household can often see details that others miss. Presented as a "salt of the earth" character, very practical and level-headed. Can sometimes appear as The Cook, or the Butler, or The Gardener (see below)
6.5. The Maid. With similar characteristics to the housekeeper, often realized as a subset. Ever present in the house, she lurks behind curtains, appears at odd hours to turn down bedclothes, or freshen up the fire. Can go anywhere without comment but sometimes gets scolded. Typically an audience favorite. A similar character to the Footman, the Assistant Gardener, the Stable Boy, depending on the needs of the story.
7. The Industrialist. Usually a wealthy older man who is the head of a business, or a engineering company developing fighter airplanes, or working on some breakthrough chemical formula, or involved in shipping and importing goods from Japan.
8. The Legal Mind. Frequently, Christie writes her stories to involve court proceedings, or to do with the execution of Wills, or the researching of family trees and marriages. Whenever this happens, she brings in this character to be a reference to the researchers. Always very intelligent, very methodical and logical, often hindered by how much information they can divulge.
9. The Efficient Professional. This is usually a woman who is good in business, and is excellent in managing business affairs. Highly intelligent. Very smartly dressed but perhaps less warm or empathetic to those around her. Excellent in conducting research, managing large databases. A classic example is Miss Lemon. Devoted to and respected by her employer but who easily rebuffs the foolish attention of single men.
10. The Rake. A young man who indulges one or more vices. Often is very successful at it, but it may catch up with him eventually. He may be a womanizer, or a gambler but always with extreme flair and charisma. Usually he is brilliant in other ways, or is unreasonably charming, which hides or excuses his flaws to others.
11. The Rival. A young man who is in competition with the main male character. Often not quite as successful, never did quite as well in school or on the sports field. This sometimes makes him bitter about life. He may have a failing that he doesn't manage well, such as drugs, gambling, alcoholism, that holds him back.
12. The Daughter. a young girl of between 7 and 12 years old. May age into another character after the Time Gap. Usually the object of affection by another character (a mother or father, Nanny or Housekeeper). May be unusually precocious and/or may die tragically and be felt as a memory or a photograph.
13. The Vicar. In every village, you'll find the resident clergyman who spends his days visiting his parishioners and learning their gossip. He is an invaluable source of information, history, and ancient artifacts.
14. The Politician. A "stuffed shirt" more concerned about himself than anyone else. His public image and the scandal of the situation often takes precedence over personal feelings and empathy for his fellow humans.
15. The Dubious Man from India. In the cosmopolitan world of the British Empire, our characters often have occasion to travel abroad. And while what happens in Vegas stays in Vegas, this is not so for former travelers who come across people they met while in India, or Kenya, or Hong Kong, or Singapore or on the steamship home. Our protagonist might be running from an unfortunate past, but these dubious travelers are there to bring it all back up again. Often a blackmailer, or simply a source of information
16. The Loving Wife. In many stories, a prominent husband can often be stubborn and prideful. In these cases, a genuinely concerned wife can take her own initiative to try to make a situation better, often by consulting our resident detective. Often not possessed of all the facts, nevertheless she feels compelled to act, seemingly motivated entirely by concern for her husband and family.
17. The Batty Eccentric. This is a character who is distinctly odd and unusual. Their behaviors may be flighty and erratic or they may perceive the world in a non-standard way. One might describe them as batty, or absent-minded. Sometimes they are involved with the occult (seances, astral spirits, ghosts). Other versions are beset with alcoholism, or PTSD, or true mental illness. Many around them view them with amusement, or tolerance, or even irritation and sometimes they are dismissed and inconsequential by the murderer. The Eccentric is similar in presentation to the Cloud-headed girl, though the latter is usually younger.
18. The Time Gap. This is not a character but is a prominent and recurring element. Its very rare to have an Agatha Christie story that does not span over at least two generations. The entire story may be relating extended flashbacks, or we might see the protagonists as children and then as grown adults. Typically, there is an obvious jump in time between the "child" and the "adult". Sometime this time gap is wider and involved historical figures.
The Adventure of Johnny Waverly: 14. The Politician.
The Hollow: The victim, Dr. John Cristow, is clearly the Rake, plagued by his wife, his mistress, and his former mistress, and he can't keep his hands off any of them. And yet he is also noble, researching cures for intractable diseases and admired by all.
Henrietta is the Energetic Young Woman, a successful artist and an independent woman who loves John Cristow but refuses to marry him.
Gerda Cristow, John's wife, is the Cloud-Headed Girl, a successful wife and the mother of two children, but continually beset with lack of self confidence, comic scenes of learning how to drive a car, and an obsequious devotion to her husband, whom she seems to constantly annoy. Often, the cloud-headed girl is portrayed as amusing, but here she is tragic.
Lady Lucy Angketell is the Batty Eccentric, constantly talking too much and saying the most inappropriate and inane things at the worst times.
Sir Henry Angketell plays the role of the Scientist, only his fascination is for guns. As is typical, this character supplies the murder weapon.
Veronica Cray is the obvious Temptrix, a movie starlet with a history with John Cristow some 12 years ago (the Time Gap) who's not above trying to seduce him away from his wife and family. She knew John when she worked in Hollywood, California (The Overseas Connection).
Gudgeon, the classic Butler, with deep loyalty to the family
We even get a short cameo of Doris, The Maid, who reports to the police that she saw Gudgeon carrying the revolver, gets soundly Scolded for her impertinence.
Edward is the Rival with John, in this case for Henrietta's affections, whom she dismisses as "inadequate." Later, he finds success with Midge Hardcastle, the classic Second who is living in the shadow of the more forceful Henrietta. Edward knew Henrietta and Midge when they were young (The Time Gap) but could only see her as "Little Midge," the scrawny girl. Now he recognizes her for the mature young woman she has become.
Finally, Poirot is aided by the generous Inspector Grange, who values Poirot's input and brings him into the entire investigation.
