The above linked article talks about how important it is for kids to read books that make them uncomfortable, since history was messy, and they need to know about history. They shouldn’t be sheltered. The books below were mentioned in the article. I’ve only read one of the books, but it was wonderful and I don’t regret reading it at all. The others are in my TBR pile. Classics.
The Grapes of Wrath
Uncle Tom’s Cabin
Adventures of Huckleberry Finn
To Kill a Mockingbird