What Christmas-based work of literature is most firmly entrenched in modern American and British culture? I would make a case for the Dickens novella A Christmas Carol. An article in the Guardian points out that while we think of the story as a presenting a "traditional English Christmas," it was published as a modern (for its time) version of Christmas—set in the city, not the country, with work and immediate family as the backdrop, not some feudal country setting with happy servants feasting with their lord and drinking wassail.

The article describes some lesser known Christmas stories Dickens wrote, to illustrate the point that he was always trying to make a case for social reform as well as to tell a good story. And it points out how little religion there is in the story, considering it's about Christmas.

I always found it interesting that so many American movie and TV versions focused on the Cratchits and even portray Scrooge spending Christmas with them, when in fact, the Victorian ideal was that he went to his nephew's house and spent Christmas with his own family—which is the way Dickens wrote it.

A Christmas Carol is still a good story, and speculative fiction, to boot, what with the ghosts and spirits. And it's a good illustration that a good writer can break any rule, even the one against passive voice.

"Marley was dead: to begin with."

I can't think of another story where I know the first and the last lines.

"God bless us every one!"

And Happy Christmas to you and yours!