Here's why:
* Imaginative Plot: The book tells the story of a family dealing with holiday craziness, including a haunted Christmas tree, a Christmas Eve snowstorm, and a family feud. These events are highly unlikely to happen in real life.
* Fictional Characters: The characters in the story are entirely made up by the author. They have their own unique personalities, relationships, and motivations.
* Fictional Setting: The story takes place in a fictional town called Willow Creek. While there may be towns with that name in real life, the events and the town's specific characteristics are entirely fictional.
Therefore, "Deck the Halls, Off the Walls!" is a fiction book because it tells a made-up story with imaginary characters and events.