It seems this one got a lot harder than I had expected - my apologies for that. This book was recently (2006) re-issued here in Norway, and from the Norwegian publisher I heard that the same book should be re-issued in several other countries as well. I had therefore thought that it would be easier.
I suggest we make this as easy as saying that the quiz is now first-come-first-served. Whoever has a good question may ask it here.
For those wanting a clue:
For those wanting the solution:
Spoiler:
The extract is from "The Mad Hatter Mystery" by John Dickson Carr. In this book we read about a hitherto unknown manuscript by Edgar Allan Poe, which is stolen. We hear about a person the newspapers call "The Mad Hatter" who steals hats all over London and puts them on display; e.g. when a barrister's wig is found on the head of a cab horse, things are set in motion.
Innocently enough, you say? When a body is found inside the Tower of London with a medieval crossbow bolt through the heart - and a stolen hat on its head - things turn serious.
About this book, which in many ways can be considered Carr's breakthrough, Dorothy L. Sayers wrote:
"Mr. Carr can lead us away from the small, artificial, brightly-lit stage of the ordinary detective plot into the menace of outer darkness. He can create atmosphere with an adjective, make a picture from a wet iron railing, a dusty table, a gas-lamp blurred by the fog. He can alarm with an illusion or delight with a rollicking absurdity. He can invent a passage from a lost work of Edgar Allan Poe which sounds like the real thing. In short he can write—not merely in the negative sense of observing the rules of syntax, but in the sense that every sentence gives a thrill of positive pleasure."