Go buy this book! Don't be a fool like me and wait patiently for the library holds to cycle around to you. Spending money on this book so you can read it before you go see the movie is a wise decision.
Even if you're not a fan of science-fiction, I suspect most people will like the man versus nature conflict of this survival story.
Starting on page one, you know that astronaut Mark Watney has been stranded on Mars. He is the lowest ranked crew member of the Ares 3 manned mission to Mars. After six days on the planet, a sandstorm carries away their communication dish and threatens to tip the Mars ascent vehicle that will carry the whole crew back to their orbiting ship. NASA orders the crew to bail out and head home. On the walk to the ascent vehicle, Mark accidentally separates from the rest of the crew, sustains an injury, and falls unconscious. The crew assume he has died and abandon him.