I read one review here on Amazon claiming that this book is rushed and badly researched, and instead recommending Excellent Cadavers by Alexander Stille. I find these claims strange and irresponsible as Cosa Nostra is excellently written in fluid and engaging prose, Dickie's sources are as sound as a pound (the book features an extensive bibliography for a work of popular history), and Stille's (excellent) novel could not hope to fill the same niche as Dickie's.
Comparing Cosa Nostra to Excellent Cadavers is like comparing a Simon Schama book (ie, History of Britain) to an Alison Weir one (ie Henry VIII King and Court). Both relate to British History, but one is far more focused and specific than the other. Excellent Cadavers was an account of Falcone's maxi trial and it's fallout, whereas Cosa Nostra is a rounded history of the organisation. The clue's in the title (well, subtitle, but you know what I mean).
This is a novel worth reading. Don't be put off by the snobs who seem to deride everything accessible as being simplistic; this work is anything but, and yet eminently easy and enjoyable to read.
4.5 stars, so I'll round it to five, eh?