Here's why:
* Nonfiction deals with real people, events, and facts. It aims to inform, explain, or persuade.
* Novels are fictional stories, typically lengthy and complex, with imagined characters and events.
* Fables are short, fictional stories with animals or inanimate objects as characters, often conveying a moral lesson.
* Essays are short, non-fiction pieces that explore a particular topic or idea, often with a specific viewpoint.
So, while essays are a part of nonfiction writing, novels and fables fall under the category of fiction.