Besides that, this novel is pretty good.
The Body in the Library begins, shockingly enough, with a body in a library. Scandalous!
The servants at Gossington Hall in St. Mary Mead discover a body in the library one morning, sending the household into a tizzy. In the introduction of the book it felt like the story was so preoccupied with its central conceit (that there was a body in the library!) I was worried it would shirk its duty to provide a compelling mystery, but that fortunately turned out to be a misplaced fear.
To be honest, I find the title of Hercule Poirot's Christmas a bit strange. It features Hercule Poirot and takes place around Christmas, but it's not about Hercule Poirot's Christmas. Oh well, the fact that the mystery is decent is more important than the title Christie chose for it.
The Argyle family has gone through a bit of a rough patch. The mother, Rachel, had been brutally murdered in their home. Jacko, the black sheep of the family, was convicted of the murder, and died in prison six months later. The family learns to accept the sad truth and move on.
However, the old wound is torn open a year and a half after Jacko's death by a visit from a man named Arthur Calgary. Calgary is able to provide Jacko with a perfect alibi for Rachel's murder, proving him innocent. Thus, the Argyles must face the terrifying truth: the murderer is still among them.
It's a catchy hook, so it's too bad the book isn't actually that exciting.
