Alright, I'm at the end of chapter 14 now, and ... did these Golden Age writers really all crib from each other to such a huge extent, or was there some sort of unspoken convention about plot and character points you absolutely had to hit in one or more of your novels (and the more in one and the same novel the better)?
So far, we've had -- just off the top of my head; at this point I'm probably even forgetting the odd item already, there's so many of them:
* A main character locking himself into a closet to listen in on a criminal conspiracy led by a masked, unknown mastermind (the eponymous Grey Mask) (cf. Agatha Christie, "The Seven Dials Mystery" and "The Secret Adversary" -- where replace "closet" by "upstairs room");
* A flippant character straight out of Oscar Wilde's "The Importance of Being Earnest", complete with droppin' his 'g's and all (cf. both Dorothy L. Sayers's Lord Peter Wimsey and Freddie Arbuthnot, though I suspect Archie Millar has a mite more grey matter inside his skull than Lord Peter's friend Freddie);
* A teenage ingenue (read: TSTL character) whose chief, albeit not sole function in the novel is to throw the bad guys into profound bafflement, with nary a clue of the danger she's putting herself in (MbD's hunch about her is definitiely, to phrase it in the language of the time, coming up trumps) (cf. Georgette Heyer and Margery Allingham -- you name it, they've written it -- and also Arthur Conan Doyle, "A Case of Identity" and "The Illustrious Client");
* A sinister plot to un-inherit an unprotected girl (here: aforesaid TSTL teenage ingenue) from a multi-million pound inheritance (cf. Arthur Conan Doyle, "The Sign of Four" and several other stories, ditto Agatha Christie);
* A letter (here: put forth in furtherance of said plot) that will undoubtedly turn out to be a forgery (an utter Golden Age staple; there's no decent crime writer of the time who did not use it at some point or other -- one of my favorite examples, at Lord Peter's own hands, appears in Dorothy L. Sayers's "Unpleasantness at the Bellona Club");
* A fairly obviously crooked lawyer (another staple, though today decidedly more than in the Golden Age novels);
* An altogether too-harmless-to-be-believed male character taking his wife abroad, from where, promptly, comes news of her sad demise (cf. Arthur Conan Doyle, "The Illustrious Client"; for the character see also Uncle Joseph in Heyer's "Envious Casca" and Sir Eustace in Agatha Christie's "The Man in the Brown Suit");
* Oodles of London pea-souper fog (cf. Edgar Wallace -- take your pick of his novels -- and E.W. Hornung; also Agatha Christie, "The Man in the Fog" and "The Crackler", though the latter is Tommy and Tuppence's "Edgar Wallace" case, so half the honors go to Wallace for that one again);
* A character who pretends to be deaf (though not dumb! How are we supposed to believe he's able to speak if he can't hear himself?) but who is anything but, and whom -- dun, du-dun-dun -- our hero follows through the aforementioned London fog (cf. Edgar Wallace again, "The Dark Eyes of London");
* A young lady using a particular name as an alias just because she thinks it's romantic, without realizing how much she's going to get herself into trouble by uttering that particular name in the hearing of the wrong people (cf. Agatha Christie, "The Secret Adversary");
* A young lady from a "good family" who's fallen on hard luck and has to work -- as a shop assistant, secretary, governess, or the like (here it's as a shop assistant) -- to earn her living (cf. half of Sherlock Holmes's female clients, several Agatha Christie characters -- e.g. Midge Hardcastle in "The Hollow" and the eponymous heroine of "Jane in Search of a Job" --; and Sheila Fentiman in Dorothy L. Sayers's "Unpleasantness at the Bellona Club");
* the wise-cracking inhabitants of far-away places -- here it's South American Indian tribes named Hula-Bula and Taran-Tula (I swear I'm NOT making this up) whose devoid-of-meaning idioms can give any "Confucius say ..." quote a run for its money;
* and, of course, a main character who (with yet another nod to Ms. Heyer and Dame Agatha) has just returned to London after several years' absence and plays at amateur detective to untangle the weeds that seem to have grown on his patch while he was away; only to find himself baffled and call on Miss Silver at the end.
As for Miss Silver herself, who has only made her first, introductory appearance at this point ... well, Agatha Christie always insisted that she had based Miss Marple on her own granny, and that she had been inspired to create the character after having had such fun with Caroline Sheppard in "The Murder of Roger Ackroyd", but given that "Grey Mask" was published two years prior to Miss Marple's first case, "Murder at the Vicarage," I can't help but wonder whether Miss Silver provided some sort of inspiration, too, after all. The two ladies are definitely not alike, but Miss Silver's initially seemingly nondescript appearance, secret sense of humor, and of course her knitting needles (!) do strike a familiar chord. The Miss Silver I've seen in other books can on occasion be decidedly more formidable than Christie's Miss Marple (in behaviour, though not in appearance, more like the Margaret Rutherford version of Miss Marple, who is not like the character from the books at all) ... it'll be interesting to see how we get from Miss Silver's first appearance to the traits she exhibits later. -- One obvious difference between the two characters is, of course, that Miss Silver is a pro, with an office and all, while Miss Marple insists that she is anything but.
Don't get me wrong; it's a fast read and I am rather enjoying it. But, dang -- half the time I keep thinking, geez, that's something, too, that I've read before!