Sorry for the late reply, I've had things to do.

In "Black Rednecks, White Liberals", Sowell traces the origins cultural problems of both the black community and the redneck white communities to Scots and other northern British peoples.

It's a fascinating book as it goes into how different cultures brought their different aspects as they migrated including not just specific European and African groups, but East Asian and Middle Easterner groups as well. Essential reading if you want to discuss race and culture, but not where I would start if you want to understand Sowell.