There sure is a big difference in Science Fiction Literature or the modern label "Sci Fi" and you have to be careful when you tell people you like Science Fiction, as they are liable to label you a wacko.
The Genre has certainly widened in the Twentieth Century and it has become very popular thanks to Hollywood making some of these classic novels into major movies.
Movies such as Star Trek, Star Wars, Battlestar Galactica, Gattaca, Logan's Run, 2001, and most recently the Blockbuster Matrix has done wonders in expanding the base of readers and fans of the genre.
Of course to truly understand how all this came to be, perhaps it might be wise to understand the entire history.
So, I'd like to recommend a very good Audio Book Lecture Series, which can be found on the NetLibrary System, easily accessible online once you have a library card to most major libraries; "From Here to Infinity: An Exploration of Science Fiction Literature - Modern Scholar Lecture Series" by Drout, Michael D.
C.
; Publication: Prince Frederick, MD Recorded Books, 2006.
This audio book modern lecture series is 7 hours and 33 minutes long, and you might have to listen to it twice to really get acquainted with the history of Science Fiction.
It explains all the authors, their styles, concepts, trilogies, series, and the sub genres, many of which are a little out there, not very politically correct and way outside the mainstream; such as Sci fi horror and fantasy.
Drout was very careful to give proper tribute and acknowledge the genius of the greats like Isaac Asimov's Foundation Series and the excellent and numerous works by Arthur C.
Clarke and others.
I hope you will enjoy this audio book as much as I have.