 Writers of all officially licensed "Charmed" literature must obtain studio approval of the content of the works – originally from Paramount Pictures until CBS Consumer Products acquired the rights to the franchise – in order to adhere to the conventions of the "Charmed" canon established by the television series.According to Paul Ruditis, authors of "Charmed" novels and comics must maintain "the rules for playing in that universe" and "the studio still has to approve the direction we take" as writers.Following these regulations, authors are given creative license but strictly "couldn't go and rewrite history, killing off established characters or suddenly creating romantic pairings that we'd never see on the show".