Much scholarly attention has been paid to how new media call for and influence the development of new literacies, but less focus has been given to exploring the underlying structure and mechanisms of projects that incorporate multiple media. Transmedia stories represent a particularly complicated and compelling type of multimedia project because of the high degree of integration among the components and resulting demand for sophisticated reading and interpretive practices. This chapter proposes a model for analysis of transmedia projects based on Gérard Genette's Paratexts: Thresholds of Interpretation and uses Scholastic, Inc.'s The 39 Clues as a case study for its application.