Actually it was Art Jensen, a professor at UC Berkeley, who wrote the earlier papers about IQ differences and race. He was thoroughly attacked for pointing out that blacks had lower IQs. No one was supposed to even think that, much less write about it.
Years later, maybe in the 90’s, two Harvard professors Charles Murray and Richard Hernstein, wrote the Bell Curve. Very few people read the book, thousands protested it. Basically they pointed out that there was a distribution of IQs and the people at the top end were reproducing and the people at the bottom end were reproducing.
The book is very long and very difficult to read without a good background in psychometrics. That hasn’t stopped critics from criticizing. It’s what they do.
The bell curve still applies and I have known some exceedingly bright black guys, one probably a genius. Obviously from the top end of the curve.
The paucity of them in engineering and science is mute testimony to the accuracy of the reports.