Didn't make it through the first chapter. Hard to trust a book on intelligence that opens with "there is no doubt that Nietzsche's psychiatric problems were compounded by his intellectual genius" as if that's an uncontroversial statement that isn't cast into doubt by all of the brilliant philosophers who don't end up institutionalized. If you're willing to cherry-pick that much in your opening statements, why should I trust your other arguments about a topic as nuanced as intelligence?