Chicago Gangs was a book published sometime prior to January, 2153. A copy of this book was owned by a crewmember of the ECS Horizon. (ENT: "Horizon")
- The book was placed on the shelf by Enterprise production staff as a subtle homage to the TOS episode "A Piece of the Action," in which a similarly-titled book, Chicago Mobs of the Twenties, was left behind on the planet Sigma Iotia II by the similarly-named Daedalus-class USS Horizon.