Yesterday, I had a friendly discussion with one of my friends who studies evolutionary biology, discussion was around human intelligence. In just the first few minutes, I started realizing my ignorance on this topic. 

He suggested many books, and one of them was 'The Bell Curve.' So far, I have only read the first few chapters, and it has already changed my entire understanding of human intelligence.
https://i.imgur.com/RIosluG.jpeg