I took up this book with the hope of understanding something more about the spectacular violence of Mexico’s cartel wars. Despite respecting the depth and insight provided by Ioan Grillo’s reporting, I’m not sure I came away any clearer on this point. Yes, there’s a lot of money involved in the drug trade in Mexico, and a lot of fighting between the different gangs and the police and among the gangs themselves. But I’m not sure what explains the level of wholesale slaughter, cruelty, and brutality that has come to characterize this criminal “insurgency” (a loaded word that Grillo has to unpack). There seems to be more to it than just wanting to send a message. One wonders if there are roots for it in Mexican culture, or if it’s more a product of American cultural influences (movies like Scarface and violent rap and videogames). Whatever the cause, a kind of moral bottom seems to have dropped out of historical norms for violent criminality, taking the cartels beyond the bounds of even common garden variety psychopathy. What happened to those better angels of our nature? Are they only fair-weather friends?