Someone else mentioned Flowers for Algernon, so mine will be ģWhere the Red Fern Grows_. Such an emotional roller coaster.

And while I won't downplay those K-12 books, I think anyone who's ever taken a Russian Literature class in college will agree that Russian authors are next level for depressing novels. Few things compare to the bleak, gray, petty, inescapable, hopeless lives portrayed by authors like Sologub, and while English translations would certainly be accessible to high school students, I'm really glad they don't include them.

Unless someone's going to say they were given The Petty Demon as a reading assignment in high school.