I've just finished reading Jostein Gaarder's The Christmas Mystery which is based on the Advent Calendar. I've stuck pretty closely to one door a day since December 1 and that worked well. I was surprised to see in my copy that I bought it in 2001. This is the second time of reading right through. I rarely read a book a second time.
Also this Christmas I bought The Everyman Christmas Strories and read it. It contains 20 stories of varying lengths by well known (Dickens, Gogol, Conan Doyle, Trollope, Tolstoy, Chekhov, etc) and lesser known (Cather, Bowen, Cheever, Paley, Munro, Ford) authors. I bought it for the Gogol (Christmas Night) which I didn't enjoy that much. My favourite was Truman Capote's A Christmas Memory. I also enjoyed John Cheever's Christmas is a sad season for the poor and Alice Munro's The Turkey season.
I also went looking for other Christmas material and found another O Henry story The gift of the Magi a classic and the original of the Jimmy Stewart film A wonderful life which is called The Christmas gift.
We have been reading the Bible a s a family, of course, and had looked at many passages to do with Christmas in one way or another. I have also been reading J M Boice's The Christ of Christmas which varies but has many good things and little clues to other good sources.
I managed the opening chapter of Can reindeer fly? on Christmas and science but din't get any further. Another time perhaps.