Book on current state of knowledge on the genetics of intelligence
A very recent review has been written on this. See

Plomin, von Stumm (2018): The new genetics of intelligence.

For some of the latest genome-wide association studies, see:

Hill, et al (2017): A combined analysis of genetically correlated traits identifies 187 loci and a role for neurogenesis and myelination in intelligence.

Savage, et al (2017): GWAS meta-analysis (N=279,930) identifies new genes and functional links to intelligence.

However, as Robert Plomin and Sophie von Stumm report, newer genome-wide association studies are on the way which account for a larger portion of the variance. So there is constant progress at the moment.

If you're interested in the neuroscience aspect of intelligence, I recommend Richard Haier's book The Neuroscience of Intelligence.