The Reformatory by Tananarive Due
This book really fits the subreddit. It was very hard to put down, constantly just one more page.
It is the story of a reformatory school, using the term school very loosely, in North Florida during the Jim Crow era.
The book depicts great cruelty and injustices. The language is true to the time period of the 1950s but the writing and story is excellent.
Well worth your time on this one