This book is officially for science geeks. If you're not a science geek, you're going to nod off and think it's terrible. If you are a science geek, you'll be playing along.
This is the story of an astronaut stranded on Mars and everything he has to do - mechanically, electrically, botanically - to get back home. It's an intriguing concept, and there's no way to write it without giving numbers, equations and hard physical facts. Fortunately, Weir also manages to make it funny by having his astronaut be kind of a dweeb. A dweeb who can last that long by seeing the humor in his situation. I would bet that astronauts are like this - both insane and heroic - but you'd have to be a very special kind of astronaut to survive for a year and a half on Mars (even future Mars with all the bells and whistles and radiation shielding).
I inhaled it. The MacGyver aspect of this man's struggle with the elements was really fun - what will he come up with next in order to save his potato crop? create a bedroom for his rover? save himself from an airlock disaster? I'm not giving anything away. Weir throws everything he can at the man - because that's what you do in this kind of a novel!