Caste: The Origins of Our Discontents, by Isabel Wilkerson. 2020.
The premise of this book is that America has a literal caste system, in the same sense as India or Nazi Germany have had. The system sorts people by attributes they can’t control. It is enshrined in law (yes, still), and is enforced by custom and violence (to this day, in case you haven’t been paying attention).
The caste perspective also addresses why poor people never seem to be able to really organize across the color line. Why? Because upending the caste system would inevitably lower the position of those nearest the bottom. And the ones currently in the upper caste (no matter how low) value their position over the gains they might make.
Wilkerson doesn’t really propose solutions, but notes that the US has never had a public accounting of the costs of the caste system (to everybody).
This book is well-written, with lots of tragic examples, and emotionally it’s a hard read.