Just finished Mafia Republic by John Dickie. It's the story of the three main Italian crime groups from 1946 to the present. And I have to say its another absolute triumph following on from his other works Mafia Brotherhoods and Cosa Nostra. If you are looking for something that reads like a novel or is based along the "Vito got whacked because he disrespected the old man" type of thing it won't be for you. He takes an academic approach to the story and lays out what each group has been up to and how they have developed since the war.
The strongest group now appears to be The Ndrangeta partly because attrition has taken a huge toll of The Mafia and The Camorra. But partly because they have had a long term policy of setting up satellite groups throughout northern Italy and establishing cells in other countries.