Needed books?

[Teleri]

I've just started to write up some books for the various nobles' libraries, as it is one of the ongoing projects listed in Community Resources.  However, I have a few questions as to the type of books people are looking for here.

Are non-fiction, informative sorts of books desired?  Reference books?  Is it possible to create fiction for the nobles to read?  I assume that certain types of fiction, like science fiction and even fantasy would be ridiculous, but would stories about fictional heroes and deeds be acceptable?

Also, is there some sort of limit on how much can be crammed into a single book object, or can I just write however much I like?

Feedback would be greatly appreciated, as then I can proceed to write even more of the stuff I already have for the nobles to read.  After all, it can get boring to be a noble at times, I know from firsthand experience.  I just wish I had stuff to read like what I'm writing!