209 Copyright © 2016, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. Chapter 12 DOI: 10.4018/978-1-5225-0477-1.ch012 ABSTRACT This chapter is based on the analysis of previous cross-media game adaptations, on empirical research, and on refection on practice with the design of a game concept for a fantasy book. Book-to-game adapta- tions are particularly interesting examples of cross-media adaptation. They not only weave the literary source text with intertexts from the game medium, but also require a modal transposition from the realm of words to a visual, interactive, multimodal medium where narrative and ludic logics intersect. This study proposes to look at diferent layers of cross-media intertextuality in the process of adaptation - at the level of specifc texts, at the level of medium conventions, and at the level of genre conventions. It draws on crowd-sourcing research with readers to demonstrate that collaboration operates through multi-layered processes of collective intertextuality through which the intertextual repertoires of indi- viduals meet to weave a fnal text. INTRODUCTION This chapter is based on empirical research and reflection on practice in the design of a game concept for a fantasy book series, Nature Mage. It looks at intertextuality in operation when author, games re- searcher and readers come together to work on a cross-media adaptation. I met the author Duncan Pile in 2012, when we started thinking about possible adaptations of his story into digital media formats, namely a game. This collaboration forms the basis of practice-based research contributing towards the UNESCO Chair project Crossing Media Boundaries: Adaptation and New Media Forms of the Book, lead by Professor Alexis Weedon at the University of Bedfordshire 1 . It is an ongoing project, and here I reflect on the path walked thus far, focusing on our thinking and work towards reader involvement and the design of a Nature Mage game. Weaving Nature Mage: Collective Intertextuality in the Design of a Book-to-Game Adaptation Claudio Pires Franco University of Bedfordshire, UK