In 2168, the Horizon visited the planet. During its survey mission, a member of the crew left behind a book, Chicago Mobs of the Twenties (referred to as "The Book"), which was discovered by the natives. The highly imitative Iotians reinvented their entire society based on "The Book," thinking it was the model for a perfect society.
In 2268, the USS Enterprise visited the star system for the second time and discovered the extent of the cultural contamination. After unusual negotiations with mob bosses on the surface, which required an intimidating show of force, Captain Kirk was able to create a loose system of government with the Federation as a "Godfather"-type figure. But unfortunately for those plans, Doctor Leonard McCoy left behind his communicator on the planet; as theirs had become a crime culture, two of the Iotians most likely stole it from him. That might have given their people the ability to copy Federation technology. (TOS: "A Piece of the Action")