Players Unleashed is a thought provoking and well-argued reconstruction of the history of digital games and the role of player modifications to such artifacts. Focusing on the wide-ranging universe of mods for the best selling game The Sims, Sihvonen presents a cogent and persuasive argument for the importance of such activities, and in doing so helps us understand the vital role that players have claimed in the development and evolution of digital games. (Mia Consalvo)