A sequel to Winslow's 2005 book The Power of the Dog which I read back in 2007, and enjoyed. In the sense that a novel containing tons of unremitting violence and betrayal can be enjoyable.
It's more of the same here. As we begin, the villain in the previous book, drug kingpin Adán Barrera, is in an American prison. Where the diligent DEA agent (and his onetime friend) Art Keller placed him at the end of The Power of the Dog. But the decades-long path of the previous book was fatal to Art ever leading a normal life; he's now doing beekeeping in a remote monastery in the desert.
But Barrera finds an out: by betraying some of his former allies in Mexico, he wangles a deal that gets him transferred to a Mexican prison. Whose keepers turn out (as Barrera knows) to be so corruptible that it's more like a luxury hotel which you are technically not allowed to leave. But re-establishing your pre-eminence as drug lord? Hey, no problem. And he eventually "escapes" anyway.
Which, in turn, brings Keller out of the monastery, and back into the game.
The book covers about eight years of the cat-and-mouse game between Barrera and Keller. With the cats and mice equipped with plenty of weaponry. There's lots of violence, some sex, and surprisingly little drugs. A lot of supporting characters to keep straight, especially on the bad-guy side; you might want to take notes.
Winslow has long been a must-read author for me. You can read this book as mindless escapism if you want. However, the underlying theme is clear: the American "war on drugs" is a massive failure; while the US gets the drugs, what Mexico gets in return is violence, corruption, and lawlessness. In a sobering dedication Winslow lists the Mexican journalists "murdered or 'disappeared'" during the writing of the book. It is a very long list.
If you want a true-fact version, I suggest Jay Nordlinger's recent article Reporting under the Gun. If anything, the danger to journalists has gotten far worse since Winslow wrote this book.