Once you're done with it check Matteo Garrone's movie adaptation.
I liked the book, but the movie seemed boring to me. In my opinion, it just doesn't show the power of the camorra, they seem just like small-time criminals in the movie, even though ferocious ones.
Because that's exactly how especially the Camorra, but also the Sacra Corona Unita and -as strange as it may sound- the Ndrangheta comes across. A lot of members of those groups -not all- look and behave as guys who came from the slums, even though they may be of immense wealth. A lot of them even live in and operate from small appartment flats or houses right in the slums.