Book to take with you to a deserted island.
You want me to pick just one book? Are you insane? It is not possible! But fine, I shall pick one (unhappy grumbles).
Of course I have to pick a Pratchett book. There is no other choice. If I had to choose only one, Carpe Jugulum would be the book I picked. It is hilarious and it has my favourite characters, the witches.