What’s it about?
Watch the trailer. It’ll do a better job describing it than I ever could.
Why should you read it?
Because The Martian is a damn good adventure story. Take a normal, albeit gifted, person and strand him on Mars. What are the challenges? What will go wrong? How will he deal with it? It moves at a good clip, though there are parts where it bogs down a bit. Switching between his viewpoint and NASA’s is an effective way to take care of the parts where it gets slow.
I should tell you: this book is *heavy* on the engineering, and it’s very Macgyver-y. It was initially self-published and I suspect that if it had gone through the normal publishing process most of the math & science would have been edited out. But it’s in there, and it helps the story because so much of the action is centered around using science to make sure he lives.