Perhaps I should explain the logic for this entry.
While the word "literature" has a much finer pedigree than "book" (literature comes from the Middle English [in the sense 'knowledge of books']: via French from the Latin litteratura, from littera), while the word "book" is quick-and-dirty anglo-saxon (from the Old English boc, bocian 'to grant by charter', of Germanic origin).
I suspect that "book" comes to mind more easily to the average person when pondering printed publications than does "literature". Just as "fuck" does, rather than "coitus"
The reason for including the additional categories is to simplify the visitor's search. By including them, he can then go directly to the category he desires, without having to wait to load another page -- literature-- then having to take the time to digest the information on that page.
It's about making it fast, easy, clear, and convenient for the visitor, which I profess to be laudable -- or, rather, perhaps I should say: I think is just a really good idea. User4 (talk) 05:15, 28 February 2015 (UTC)