Not so much an essay on the overall state of immigration (demographics, policy, etc.), as it is a probing of the hardship facing children leaving (usually fleeing) Central America and attempting to find a home in the United States, the work shines because of its brevity and density.  Luiselli works in enough sobering stories, focusing on several children in particular, to bring her reader out of the heady world of political debate and media coverage and back to the people at the center of things.  An easy and very worthwhile read.