An instant sci-fi classic. The premise of how a lone astronaut stranded on Mars could survive is great, the main protagonist is awesome (the supporting cast is fun too), and the writing is intense and engaging. As is typical of programmers, Andy Weir has an obsession with getting every detail precisely right, so at times, the book straddles the line between fiction and a Mars-survival-how-to-guide, full of math and science details (as a programmer, I enjoyed nerding out on these parts, but they are not for everyone). However, other than that, it's an edge-of-your seat thriller similar to Gravity. Great stuff.