Allan May's books about Youngstown and Warren are pretty interesting.

Stephen Schenider's book "Iced" I think is the best book on Canadian organized crime ever, one of the few books that at the same time offer a general picture of history of crime and don't lack detailed descriptions of specific cases and examples. Usually, it's either detailed descriptions OR a general picture.

Daniel Waugh's book on Prohibition gangs in St.Louis are good too.

To be honest, in my opinion it's difficult to choose one or even several best authors, because usually each of them is specialized in history of a particular territory; Selwyn Raab in New York, Allan May in Ohio, Scott Deitche in Florida etc, each does a good job in my opinion.

Willie Marfeo to Henry Tameleo:

1) "You people want a loaf of bread and you throw the crumbs back. Well, fuck you. I ain't closing down."

2) "Get out of here, old man. Go tell Raymond to go shit in his hat. We're not giving you anything."