+1 for the Good Rat by Jimmy Breslin (about the Mafia Cops). I love Breslin's writing style: tongue in cheek humor while discussing a murder.

In addition to 5 Families, some of my other favorites are:

Last Days of the Sicilians - the Pizza Connection case.

Mafia Inc - the Montreal / Rizzuto family.

The Outfit - Good history of Chicago

Best way to catch the smart ones? Get an idiot working for them.