This chapter provides an account of canonicity from a number of perspectives. It explains the broad range of meanings of canonicity that then leads into the emergence of imaginary world canon, most notably in reference to Ronald Knox's satirical essay, "Studies in the Literature of Sherlock Holmes", a work that set out to deliberate on questions of canonicity regarding the famous detective's adventures from the bottom-up. This leads into an examination of the way in which authorship and canonicity are intrinsically connected as a method of branding imaginary world fiction as legitimate and accurate through the lens of Star Trek. Like many imaginary worlds, the Sherlock Holmes universe is brimming with texts, the vast majority of which were not written by original creator and author, Arthur Conan Doyle. The chapter discusses the importance of canon as both a fan concern and the industrial logic of "commodity braiding" as a way to provide genuine interconnections between imaginary world narratives.