I'd watched the first two seasons of this on MHZ before I'd started on the series of books. If you love this series, you absolutely must get the books and read them! Start with "The Crocodile" which takes place before any of the "I bastardi" episodes, but is an absolute marvel of a book, introducing you to Lojacano and Piras, as well as Maurizio De Giovanni's style of writing. I came to love Sicily through the Montalbano books, and these, though quite different, give one a great appreciation of Naples, much more than one gets by visiting the Musei or going to see Pompeii.
Then the first actual "bastardi" book, where you are introduced to the other police officers you will know through the series is a must. That book is essentially covered by Season 1 Episode 1, but adds in much of the background from "The Crocodile." The casting is fantastic--I can't imagine anyone seeming more like Lojacano than Alessandro Gassman. And the rest are similarly well cast, down to the idiotic flashing of sunglasses than Angrisiano does playing Aragona. He's perfect, as are the rest. Very well done. This series is as well-matched to the books as the Montalbanos, or the Campion series, or Suchet as Poirot.
Assolutamente perfetto!!