Where Science Fiction is the writing of stories derived from some form of extrapolation from the laws and theory of science, there is a subgenre of books which take well-established settings and worlds and take a documentarian, analytical view of how that setting fits into, illustrates, or contrasts with the "real world". However, there is more than ample evidence to make the argument that a lot of it is either merchandising, trying to milk a franchise, or a Fan Wank gone horribly and publicly wrong.