Haven't been all the way back through the Malevolent tag today so apologies if people have said this already, but fun note about that puzzle book Faroe has with her at the end of Threshhold ep 1, the Torquemada Puzzle Book:
It did exist, was published in 1934, and contained, as Faroe noted, a large number of crosswords and acrostics and etc. That's not the main thing it's remembered for now, however.
The main thing it's remembered for is a very, very difficult puzzle in the form of a 100-page murder mystery. The challenge of the puzzle is to put all 100 pages of the story in the correct order; the solution has never been made public.
The title of the story?
Cain's Jawbone.











