Uh-huh, you see many publishers will tell an author that they had written a book, when in fact they had written a short prose. Or Authors think they had written a novel, when in fact it was a novella.
The 5 main types of Literature are:
5) Graphic Novels. (Not the SNVL, LGBT, M/M, BDSM kind) but actual Picture Comic Books.
The other types of literature includes, Media (like phamplets, etc.) Fables, Folklore, and Oral or Audio literature. But these forms of literature rarely cause contention.
Prose is divided into different types.
a) Novels - Fiction novels are over 80 000 words or over 350 pages long, especially if they are geared towards adults. It doesn't matter what genre they fall under... these are real books. Anything less is a short prose and cannot be classified as a book. The only time a publisher will tell you that your 50 000 odd words are considered a book, is when they are trying to cut costs in pre-pub work or printing. Having said that, the only exception to the rule will be Young Adult Fiction Novels. They may consist of 55 000 words or can be up to 150 pages long, since let's face it, teens have short attention spans. More than 55K words and they'll complain that you have written a Tome.
b) Novella - anything below the above is considered a Novella or Short Story, thus it is not classified a book. So next time an author tells you they have published hundreds of books, ask them about the word count. or number of pages. Any one can knock out a 150 page Novella a month.
c) Anti-novels - When an author strays from the norm in terms of plot structure, character portrayal and point of view, and the protagonist's actions contradict that which is considered normal in society, then that book is an anti-novel. My best modern day example is the literary genius of Ian Hudson.
d) Manifesto - any written declaration by a person, group, or party detailing their motives or opinions is a manifesto. These days we know them as Mission Statements or Political proclamations, but many authors have opted to write Manifestos when they have more to say about a particular subject that they are passionate about.
e) Belles-Lettres - These are light, entertaining and sophisticated writings normally in the form of essays, but poetry as well. Valued for the aesthetic sense rather than the information they contain, The most famous for writing Belle-Lettres is the legendary Paulo Coelho.
f) Diaries. Though diaries are personal narratives that depict events from a certain timeline, they are considered a type of Prose. They fall under Prose rather than Non-fiction, because non-fiction books are close to between 75K and 110K words long depending on whether or not they are Autobiographies/ Memoirs, Historical Biographies, Academic handbooks, Journalism, Travelogues, Manuals or Self-help books.
There you have it.