Books of fiction are usually divided into

To main parts novel and story

Okay, I don't know what case you are talking about but here are the different cases:

Beginning, middle and end. The beginning basically introduces a book. Often, there is a little problem before the major problem in the middle. The little problem may lead to a big one, or there may be many problems that need many resolutions. The end must not be as exciting as the middle, of where the problems occur.

Books of fiction are divided into novel and chapter books.