I never realized C. S. Lewis wrote science fiction novels!

[Shajon]

I happened up on his Space Trilogy at the library and checked it out.  I haven't started reading it yet, but I plan to this weekend.  (Just as soon as I finish reading Rhett Butler's People.)

From Wikipedia: The Space Trilogy, Cosmic Trilogy or Ransom Trilogy is a trilogy of three science fiction novels by C. S. Lewis, famous for his later series The Chronicles of Narnia. A philologist named Elwin Ransom is the hero of the first two novels and an important character in the third.

The books in the trilogy are:

Out of the Silent Planet (1938), set mostly on Mars.
Perelandra (1943), set mostly on Venus. Also known as Voyage to Venus.
That Hideous Strength (1945), set on Earth.