It's an excellent book, whether on Sicily or Italy more generally, and it is written by Peter Robb. It is also an excellent book about Naples:
Every transaction in Naples, every social act, requires a complex and at times exhausting social trafficking, a subtle and insidious play whereby the socially weaker player contrives to ingratiate himself and at the same time take the piss out of the stronger, to catch the other wrong-footed, but delicately, imperceptibly, to introduce some subliminal sense of social unease that may then be used as leverage. To create if possible a sense of obligation, of gratitude, even dependency. There isn't necessarily any malice in this. It's an old art of creating strength out of weakness and Neapolitan amiability itself is part of it. In Naples it has always been a necessary art of survival. If respect is the crucial concept in social relations in Sicily, the Neapolitan counterpart is its opposite, disrespect.
I also liked this sentence:
In Naples you remembered being happy and never why.