They make a big deal about the kids in the underwear...
It wasn't long after I found out that my family was from the Avellino province of Italy that I also found out most of that part of southern Italy is the prime territory of the Camorra, the mob that runs Naples and the surrounding area.
Really, you should read the book, but to make a long story short:
There are more than 25 Camorra "clans" in southern Italy, and unlike the Cosa Nostra, what we think of as the traditional Sicilian/U.S. Mafia, they don't have a pyramid structure. It's more horizontal, which makes it harder to take down the whole mob. It also makes for a lot of violence between the clans themselves, which have apparently resulted in thousands of murders in a relatively short time period.
The Camorra infiltrate every level of society, right down to controlling who moves in and out of the Naples project highrises, "persuading" citizens to vote their candidates into town governments, controlling the milk and fish industries and earning Naples a spot as one of the drug capitals of the world. They shuttle whatever they want through and from the Port of Naples, one of the largest in the world, earning millions in high-quality designer-label bootleg clothing. They control and profit from nearly every step of the construction industry, from fixed bids to waste disposal, which is really the creepiest of it all. One of the ways that Camorra disposal companies get rid of toxic waste is to occasionally mix it in with concrete AND BUILD HOUSING FOR ITALIANS WITH IT. People are literally being poisoned by their homes.
To be clear, the movie is all fictional characters, but based on the book, which is fact. I think, though, that they could have done a better job fleshing out what's going on, which would be crystal-clear to Italians, but not really so much to an American viewer.
One of the five intersecting plot lines is a gang war with a group of "secessionists" splitting from their clan, which closely mirrors what the Italian media called the "Scampia wars" in, I believe the Di Lauro clan. The movie kicks off with the act that starts the war, but it's not really that clear until later on.
Don't get me wrong, the movie is excellent. Its stories hew pretty close to the book, and if they're to be believed, Naples is fuuuucked up. I used to really want to travel to Italy and see where my dad's side of the family came from, but I'm not so sure now. One thing it does very, very well is deromanticize the ideas that most of us have about the Italian mob (a.k.a. the Godfather mentality), because in Naples it just isn't like that. It's more like the streets of Baltimore on The Wire, only the gangs are much more organized and in control of the local economy. In fact, in the book, Saviano notes that Mario Puzo's original character for the Godfather books was most likely based on a Camorra boss, rather than a Cosa Nostra figure.
Gomorrah isn't out in the U.S. yet - I stupidly ordered a copy from Amazon's UK site without thinking that it would be a Region 2 DVD I can only watch on my computer - but once it is, I highly recommend it.