Inventing a Universe examines the creative and critical writing of an Internet fan fiction archive. First, I suggest that persistent theories of fan writing, including the influential notion of fans as “textual poachers,” have not adequately made visible the work of reading and writing that goes in at such sites. I reframe Internet fan fiction as the work of amateur writers drawing on composition studies work on discourse communities and student writing to offer new ways of reading these texts and textual practices. Second, analyzing the discourse conventions and texts of a particular Buffy the Vampire Slayer fan fiction archive, Different Colored Pens, I argue that members of this site share an explicit collaborative project of using fan fiction to help one another improve as readers and writers. This dissertation, which is among the first academic efforts to focus on and analyze fan fiction feedback practices specifically, will contribute to the rich and growing literature on the ways that online communities of amateur writers, including fan fiction writers, collaboratively develop their writing skills.