There are a lot of EOTW books out there and I've read most of them. I read Alas, Babylon when I was 9 or 10, made a big impression on me. (I won't date myself by saying it was published when I was 9 or 10)
Footfall by Pournelle/Nivens is another favorite, though more scifi in nature.
'Day of the Triffids' is a good one, although the British-made movie sucked. The same author also wrote a book about the earth reversing its rotation. Premise was when the earth started to slow down the atmosphere didn't and the winds knocked everything flat.
Babylon is the most realistic and hopeful book in the genre of man-made EOTW scenarios. Just contrast it with "On the Beach" (Nevil Schute?). Yikes.
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In a crisis one does not rise to one's level of expectations but rather falls to one's level of training.