I am an avid fan of science fiction. I enjoy other works of fiction as well, but science fiction has always been my favorite. I just stumbled on a great piece about science-fiction-as-literature written by Joanna Russ in 1975: Towards an Aesthetic of Science Fiction
This is an academic piece and thus somewhat dry. Nonetheless it is worth the effort to read for those of us entranced by science fiction. Ms. Russ says “That science fiction, like much medieval literature, is didactic.” She extends the medieval literature analogy in various convincing ways.
Medieval literature is a startling choice for the most interesting analogy to science fiction among traditional forms of literature.