There are only three banned porn varieties I know of (depending on jurisdiction), which are child porn, bestiality porn, and nonconsensual/revenge porn.
And calling those things "books" is just nonsense. You know what we are talking about when we say "books", and it isn't that.
And calling those things "books" is just nonsense. You know what we are talking about when we say "books", and it isn't that.