Northern Mexico for this book's purposes is everything north of the Trans-Mexican Volcanic Belt that crosses from ocean to ocean about the latitude of Mexico City. The first chapters set the stage by talking about the region's geological and paleontological history, human geography, and conservation laws. Each of the rest has a more specific topic, usually a particular taxon in a particular subregion. Most chapters are about tetrapods or plants. Because the chapter topics are so narrow and northern Mexico is so large, the coverage is less complete than the state study of Yucatán I read recently. The focus is more on biogeographical patterns and less on inventory of species and economic exploitation. There's plenty of biogeographical complexity to talk about, since the land area is fragmented by the Gulf of California and two widely separated mountain ranges, the Sierra Madre Occidental and the Sierra Madre Occidental. It was heartbreaking, and that's not a word I use lightly, to read the analysis of threats to vaquitas in the chapter on cetaceans in the Gulf of California, knowing that the last vaquitas are likely dying in totoaba poachers' nets as I write. The introduction congratulates itself on the fact that most chapters have at least one Mexican author (the others are mostly from the USA), but considering that they are all in English even though the book is supposed to be first and foremost for Mexican conservation organizations, it still has a ways to go on that score.
Most chapters are not overtly violent. The authors of a chapter on fish carried out new killings for it and a chapter on scorpions gives explicit instructions on how other researchers should kill them. On the other hand, one chapter gives important information on a human threat to wild animal lives, namely accidental electrocutions of birds (especially ravens and hawks) on power lines, which power companies can greatly reduce by designing their poles more safely.