Christmas!

Today we received our first Christmas card! Actually it is not a card, but an Advent calendar. Inside are twenty five questions and the answers are inside 25 little doors on the front - one for each day up to Christmas Day! I have cheated and read the first but will open 'door 1' on 1st December. The question was:
1. Which book begins: 'Christmas wouldn't be Christmas without any presents'?
I know the answer (I think?) but will check on the given day.