SCIENCE! HARD SCI-FI! MOAR SCIENCE! DON’T GO, RUN TO BUY AND READ THIS!
all-caps-words aside, this is easily the best hard-scifi book I have read in the last five years or more. Except of the beginning assumption that humanity somehow convinces itself to send humans to Mars, everything is so very plausible. Watneys speech / log entries have just the amount of black humour I encounter very often when one of our projects goes south.
I could gush more and more about this book, but other reviewers already have done so. Suffice to say that it cost be two consecutive days worth of sleep just so I would know what happens at the end.