Hillbilly Elegy is one of the most fascinating books I've read in awhile. It gives a cultural context to this group of Americans. It is written by one of their own.
It's about the Scotch-Irish people who came to the Americas and dominated Appalachia's gritty coal mines until coal fell out of favor; the risks of coal dust finally proven not just for miners, but for everyone else as well.
The decline of mining drove the ambitious among them to the industrial cities of the north: Detroit, Cleveland, Milwaukee, Cincinnati, etc., where they populated the automobile and other factories then fueling the world economy.
J.D. Vance describes his people as "feuding" folk - citing his own ancestral connection to the legendary Hatfield-McCoy feud that apparently went on for generations. He asserts that this fighting nature is so ingrained in the culture that the only ones who escape it are those who marry outside it.