A great book on the political economy of gangs is written by Sudhir Venkatesh
in "Gang Leader for a Day". In this book Sudhir reports on his adventures as a Chicago graduate students studying the activities of a gang. He got access to the innerworkings of the gang by getting the interest of gangleader JT. Sudhir gain the trust of the community over the years which provides him access to interesting data on the earning of the gang members and other residents of the Robert Taylor project, the way the gangs and police monitor and enforce. Sudhir is nowadays a professor in Sociology at Colombia University.