I've got to say that despite all the "tech talk" at times, I really enjoyed this book. Mark Watney is funny, inventive and definitely the type of guy you want around in an emergency. The scenario - being trapped alone on a planet - is terrifying to even contemplate, but through a series of ingenious well thought out idea's our hero manages. The only downside for me personally was I felt that I was sometimes "overpowered" by the sometimes incessant "tech talk". It tended to distract me from the real story -what was happening to Mark- with jargon I didn't really need to know every small mathematical detail. It was fine in the beginning but I found it a little wearing towards the end. Hence 4 stars instead of 5. Overall a great story that is beautifully crafted.