Do I even need to explain what this one is about? Epic spanning a whole Mafia family sprawled across a decade. Onto review:
Like I said in the first comment, the thing that pulls you in immediately is the perfect setting up of the magnetism, the why clans work. The comfort of belonging, the empowerment of feeling backed up by your people. And of course, the unsubstantiated but very present sense of menace when you skirt it's edges.
I don't know that those are very clear to someone born to privilege. I think it's possible for many to read this book and get horrified "in a straight manner", by the violence and the getting away with it. Personally, much of my horror while reading was the realization that I was doubtful about how far was too far.
To explain: law, while a laudable thing that one ought to strive to follow, is not the same as justice. It's supposed to strive to be, but then, it is forged by people with the power to forge it. Humans, supposed to be working for the good of the many, but always with personal views of what that is. And that's with the best possible setting. Government, law enforcement, all the political and economical structure, also follow the same path. Made by people for the people. Which people?.
So when you are part of the demographic that is not the controlling one, or live in a country with a government you distrust, the rounding-of-the-carts family first, then friends, then we'll see thing seems the safe way to go. I started to have all this thoughts about how far I'd be willing to go, how much I'd flaut the law for my borther, or my best fried, or my child... Let me tell you, it is scary to realize while reading a book that your moral center is not a fixed thing. That's where the mind-screw tag gets deserved.
As for particulars, I have to toast the verisimilitude. No Sicilian's in my tree, but enough Italian blood to recognize many traits that resonated. The appearance of self-deprecating nature that is really pride, the cheerfulness that barely conceals the deep-well of potential violence, the strange to me (since I'm a couple generations removed) highly passionate, forever contentious marital relations, where the man rules, sometimes violently, often unfaithfully, but the woman might stick a knife in his groin. And they'd remain happily married for a couple more decades... yeah, actually, that comedy was my grandparents life. We can laugh about it with mom now, some days.
As for the vengefulness, that's an epic I have nothing in my life to make a parallel, because damn.
By the way, I started to read a bit about Sicily and wiki-walked to the Sicilian Opening stub. I'm so sure the man that named it was being facetious. I mean, really, a very agresive response that does not directly menace an opponent's piece?