while they are a little self serving, William Roemers books are pretty good as far as outfit stories go. "The Geniune Godfather" as DE NIRO mentioned and also "Man Against The Mob". Also a good book that definitely flys under the radar is a book by Michael Corbitt and Sam Giancana called "Double Deal" gives some good insight on the corruption of small precincts in the outer suburbs of chicago.

As far as my all time favorite books go i have to list books like Murder Machine, Blood and Honor, Mr. Capone by Robert Shoenberg, tough jews by rich cohen, Joe Dogs (Autobio of Joe Inauzzi), Underboss ( jerry Angulio story), The Westies by TJ English etc....

I could go on and on really, some are better than others but most of them i can find at least some of it interesting... except for Phillip Carlo's stuff, can't stand any of his books.