Chapter 4 was odd.
My doubts about the chapter were introduced by this statement:
"Although Poe is not one of the writers she mentions in An Autobiography as being an influence, Agatha Christie took his template of a murder and its investigation when she began to write The Mysterious Affair at Styles, 75 years later."
I would argue that she took more inspiration from Holmes than Dupin as the parallels to Holmes and Watson - even to the extent of spoofing - are far more pronounced. So, while Poe may have set the template structure, and Holmes and Watson are a variation of Dupin and his narrator friend, I'm not sure Curran's phrasing is right here as tracing Christie's Poirot back to Poe seems like a generalision in the sense that all detective stories with this setup tract back to Poe. To me this is misleading, but Curran may just have included it to give an abbreviated history of the format.
But then Curran goes on to compare Christie's works, or elements in them, to Poe's Dupin stories. While I remember Christie referencing Chesterton and others in her autobiography, why would Curran choose to draw comparisons to the one author who is not mentioned as an influence in her autobiography??
This does not make a lot of sense to me.
And then Curran goes off on what seems to me another tangent:
"So, Christie’s output adhered to most of the conditions of Poe’s initial model, while simultaneously expanding and experimenting with them. Although Poe created the template for later writers of detective fiction, early in the twentieth century two practitioners formalised the ‘rules’ for the construction of successful detective fiction. But these formalisations, by S.S. Van Dine and Ronald Knox, writing almost simultaneously on opposite sides of the Atlantic, merely acted as a challenge to Agatha Christie’s ingenuity."
He compares her works to Van Dine and Knox, and while adding in Van Dine's "Twenty Rules for Writing Detective Stories" and Knox' "Decalogue" of similar rules, he then goes on to completely dismiss their influence on Christie's writing:
Christie knew of S.S. Van Dine; some of his novels can still be seen on the shelves of Greenway House and she mentioned him in Notebook 41, although it is doubtful if she was aware of his Rules until long after they were written.
But as will be seen from a survey of Christie’s output, many of the Rules laid down by both Knox and Van Dine were ingeniously ignored and often gleefully broken by the Queen of Crime. Her infringement was, in most cases, instinctive rather than premeditated; and her skill was such that she managed to do so while still remaining faithful to the basic tenets of detective fiction.
This feels like a lot padding, or in any case rather clunky and misleading writing.
Also, curiously, there is not a single mention of Conan Doyle or Chesterton. Not one.
Needless to say, doubts have settled in about this book now.