Wad’s “Before the Dawn” was generally good for the time it was written. A fair amount has changed even in the last couple of years. I’ve just pre ordered this book and will see. To me, there is always the danger of working with too large a group so the generalizations don’t really mean anything. In Africa, you see great variations physically between the San, Bantu and Ethiopian for instance. The same is true for all racial groups.
You are quite right.
There is an obvious problem here.
We can over-focus on the fact that “races,” as defined by Wade, are not really distinct separate groups. Which causes us to ignore the very real commonalities.