In new research which studies the social relationships of organized crime in Chicago in the 1920s, Chris M. Smith and Andrew V. Papachristos were able to take advantage ofthe availability of thousands of notes and documents on Al Capone’s criminal network. By applying network analysis to the criminal relationships in Capone’s gangs they find that multiplexity – when two people have more than one relationship – was a rare but very relevant part of Chicago’s Prohibition era network. Their research highlight the ways that multiplexity links the underworld and the upper world — a process that organizes crime into mainstream society.