Underground Airlines is a crime thriller with a twist. It takes place in the modern day United States, but in an alternate world where there was no Civil War, and the southern states were never compelled to give up slavery. Instead, the U.S. stayed together, and the northern states compromised with the southern states. The practice is legitimized and regulated. Advances in technology make the tracking of slaves and the prevention of runaways more and more efficient. The manufacturing industry is thriving in the slave states thanks to free labor and a consumer base that has grown accustomed to cheap products.

The one problem I had with the book was with the female lead, who started out as an intriguing character, but by the end of the book morphed into the kind of personality-less assistant to the male protagonist who shows up so often in the movies. Otherwise, I thought the book was well-written, and the narration in the audiobook is top-notch. The author takes real-life imagery, people, and historical events, and re-imagines them in light of this world where slavery is still legal. The depressing premise seems absurd at first; but if you think about it, slavery persisted over 75 years after the drafting of the Constitution. Is it that much of a stretch to imagine it could have lasted three times longer if historical events had gone a little differently?