I'm currently reading "The Man Who Got Away: The Bugs Moran Story: A Biography" by Rose Keefe. Its a highly detailed biography on little known Northside Chicago gangster George "Bugs" Moran. Keefe also wrote a biography on Dean O'Banion who was Moran's ally/partner on the Northside. Another book Keefe wrote was a biography on NY Jewish gangster Jack Zelig.

I've only read the O'Banion book along with the Moran book I'm currently reading. Both books are highly informative, and shed some light on two personalities, which have pretty much been neglected by historians/researchers.

Another book I'm contemplating rereading (based on what others have said on here) is "Five Families" I knocked this book off during a weekend hiatus when I moved into the townhouse I currently live in and didn't have cable/internet installed yet, I was bored outta my mind, and had nothing better to do. I enjoyed it so much I might read it again.