It's depressing how conventional it has become for a relatively intelligent population, like the HN audience, to only know about criticisms of IQ and basically nothing about its positive value. But witness the credulous reception for Taleb's slapdash work in these comments, and the hostility to basic technical criticisms of that work.

If you are interested in knowing about the thing itself, and not just criticisms of the thing, I invite you to pick up, for example, Stuart Ritchie's book https://www.amazon.com/Intelligence-That-Matters-Stuart-Ritc...

And before you get upset about the title, the book is from a survey series called "All That Matters". It's not claiming that _intelligence_ is "all that matters".

Asking questions that imply you've never bothered to read anything about the topic isn't a good way to try to get other people to engage with you.

But if you're looking for a brief overview, you could read https://www.amazon.com/dp/1444791877/