The bookshop in question is Interstellar Master Traders in Lancaster. ppint is a longtime contributor to
alt.fan.pratchett
, well-known for, amongst many other things, maintaining a number of that group’s “Frequently Asked Questions” documents.
The question Susan asks in this book. Many people have found it difficult to determine just what this question is. Perhaps this is because the Oh God of Hangovers asks it first, on p. 153, after which Susan turns to the Death of Raths and relays the question to him: “‘Actually… where do [the Tooth Fairies] take the teeth?’”
When Hogfather was being written, Terry answered the question what it was going to be about as follows:
“Let’s see, now…in Hogfather there are a number of stabbings, someone’s killed by a man made of knives, someone’s killed by the dark, and someone just been killed by a wardrobe.
It’s a book about the magic of childhood. You can tell.”