Read Gwern’s review:

Aside from that, it’s a lot of wasted opportunity. For instance, the income~IQ relationship. The discussion is extremely economisty. Not even mentioned that people vary a lot in their job preferences for job types which is linked to the wages of these jobs. This creates a lot of noise for the relationship at the personal level, but not so much at the group level unless groups also differ strongly in job preferences, which they probably don’t. No one knows much about this because apparently there is little interest in e.g. race differences in work-related preferences! Only sex differences have a reasonable amount of data. Typical economist to assume that everybody wants the same things. All interchangeable, no individual differences. All the evidence of course says “that ain’t so”.

No discussion of the relative instability of wages or income. When one uses many years averaged (and preferably register based, not self-reported!) income, the correlations go up a lot — just as the heritability does.

Pretty weak discussion of the negative effects of low ability immigrants. Again, very economisty. Lots of discussion of wages, no discussion of crime! Some abstract discussion of voting patterns and the possible negative long-term effects on political institutions, but little real data. No mentioning that lots of low skill immigrants have low wages that don’t pay for their expenses for the amount of police time, school time and benefits received. Not to mention their lower employment rates. No mentioning of actual policy results such as tons of wasted time and money on spurious egalitarianist pseudo-anti-discrimination laws (e.g. affirmative action), which, because it displaces ability, also lowers output in line with the O ring model. Or the loss of freedom of speech due to perpetual complaints from Muslims.

As I said, wasted potential. On the bright side, it’s certainly better than much other pop sci on IQ and hopefully it inspires some people to get more research done.