I was actually thinking that we would just have books in the media section, because media would include books, as well as music and movies. Plus things that are in-between, like web pages or various kinds of interactive media. Books are just one example of a large category.
https://zeldadungeon.net/forum/forums/media.108/
But it does occur to me that we could also create a social group for books, just like Zachie suggested for the Mario forums. I did see something called Lynel Book Club in there as a joke, but I presume there's nothing stopping anyone from creating an actual book club. The advantage of using the social group feature for this, is that people would be able to easily host their own separate book clubs to accommodate different tastes in literature.
https://zeldadungeon.net/forum/social-categories/general-discussion-groups.130/
In principle, I don't object to the idea of creating a book subforum in the media section, but it seems like there are a lot of existing threads about books there that would potentially have to be moved if this were done. Also, people might not think about the subforum and just create book threads in the media section itself... which would also have to be moved. In other words, because people are already accustomed to using the media subsection this way, changing the structure now would involve a learning curve for people who are used to the old way.
As a compromise solution, though... what if we just had a [Book] thread prefix for the Media subforum, so that people can emphasize that their thread is about books? Sort of like how General Gaming has Nintendo, Sony, and Microsoft prefixes.