I think there was a couple of supplementary picture books put out by HBO that gives a lot of background. Back when the show first started, on HBO's Soprano web page, they had a mock FBI surveillance log of Tony's crew, and it was hilarious. I should check one of the wayback websites to see if it can be retrieved.
"...the successful annihilation of organized crime's subculture in America would rock the 'legitimate' world's foundation, which would ultimately force fundamental social changes and redistributions of wealth and power in this country. Meyer Lansky's dream was to bond the two worlds together so that one could not survive without the other." - Dan E. Moldea
