Over on PW's Genreville, I found this visual depitction of the history of Science Fiction.
You can use the link to read more about it and enlarge it.
This graphic been picked up by many of the blogs and websites I monitor, but I saved it for posting today because Spring Break and Midterms are over at Dominican and we are back to the genres. Tonight we will be talking about Literary Fiction, Mystery, Psychological Suspense, and Science Fiction. More about this grouping of genres and links to the student's work for this week later today.
For now, spend some time looking at this graphic history. I have looked at it a few times now and have been struck by how effectively it depicts this complicated genre. Of course it is not perfect, but I dare you not to get lost in following a path of two.