Thanks for the added suggestions.
All Quiet on the Western Front (1930)
zelmo, the first time I tried to read that book, it gave me nightmares. The book is (in my opinion), horrifying.
I did eventually make it through.
Based on that emotional experience, I will wait a bit before introducing that one to my children. It's an important story, but one that I believe should be taken in the context of a little more life's experience.