The answer is actually it depends.
While we have expanded sections to allow for computers, we still only focus on items that facilitate games. For example, we do not track software for computers. As a result, any book that is added to the site must be gaming related. When it comes to books or magazines, the content is not what we are looking for, rather what is represented on the cover. If a book or magazine cover has a picture from a game, a logo or a title, or that of a console, then it can be added.
I'm fairly certain those books had been added to the site in the past but have since been removed.