As you can see right there in the subtitle, the author, Reihan Salam, is the son of immigrants, specifically Bangladeshi. And he's obviously a success story. And yet…
It's a relatively short book (under 200 pages) and Reihan's thesis is pretty simple: our current immigration system lets in way too many low-skilled immigrants. Why is this bad?
Well, first, we should note that it's a pretty good deal for those low-skill immigrants. Their lives are measurably improved by coming to America, by accepting employment "doing jobs Americans won't do". And we natives should forthrightly admit that we benefit from their inexpensive labor making goods and services more affordable for us.
Except it's a bad deal in nearly all other ways. While low-skill immigrants improve their lot, they are pretty likely to be stuck at the bottom as far as American economic strata go. Opportunities for economic mobility are close to zero. As are opportunities for social mobility: they are likely to be segregated into low-income low-status communities; their kids are going to attend bad schools. What we've thought of as "assimilation" is increasingly off the table.
Reihan advocates high-skill immigration. Fine. And thinks Yet Another Amnesty for the current crop of illegals is probably desirable (and inevitable). But it must be coupled with a "this time we mean it" strengthening of border security, e-Verify, and whatever else necessary to stem the low-skill tide.
He has a number of other interesting suggestions. For example, reverse immigration, where (relatively) affluent Americans relocate down south, and start employing people there. Government policies to reform (especially) Central American economies, allowing more of their people to participate in the global economy.