AKMA and Dorothea have been discussing 'Book People' - I am certainly one (why else would I be writing this at half-past one on a Saturday night?).
It is certainly hereditary. (My father extended our house when my youngest sister was born. He added a small playroom, a small bedroom for my middle sister, and a large room lined with book-cases and a desk for him to work in. Since have now left home, the other 2 rooms are full of books as is the more recent loft conversion, as is his offfice about a mile away).
Here's another one - Book people would rather spend an hour on public transport (where they can read) than 20 minutes driving.
Anyway, I recently encountered The Folio Society - a company who does understand 'Book people', and they have successfully tempted me to sign up...