I originally bought this book for my husband, and then ended up reading it myself. My husband enjoyed the book enough to ask if the author had written anything else (this doesn't happen very often).
I found this book to be an enjoyable, action packed, fast moving and funny novel about the adventures of astronaut Mark Watney accidentally left on Mars. The mechanical details were a bit above my head (i.e. can't tell how accurate they are), but I loved the botany and science details. Too bad my potatoes never grow as well as Watneys!
As far as I can remember (I was "reading another book while "watching" the movie), the book is a bit different than the movie, but not too much.