3.5, rounding up to 4. The real strength here lies in the emotional impact - The Book of Unknown Americans is simultaneously sad and enraging and hopeful, which is a difficult balancing act to pull off! But it does it well, and I was genuinely affected by the fate of the characters.

It's told from a variety of perspectives - the first person viewpoints of most of the major characters. While this is an effective tactic for giving breadth to the story, I'm not sure that Henriquez really differentiated the prose of each character enough for me. It can be really difficult to make characters sound unique, and to me here it was more like (as is actually the case, of course) a narrator speaking for a number of different people rather than a collection of individual voices.