This book argues that fans' creative works form a cognitive system; fanfic, fanvids, and gifs are not simply evidence of thinking, but acts of thinking. Drawing on work in cognitive linguistics, neuroscience, cognitive philosophy, and psychology—particularly focused on 4-E cognition, which rejects Cartesian dualism–this project demonstrates that cognition is an embodied, emotional, and distributed act that emerges from fans' interactions with media texts, technological interfaces, and fan collectives. This mode of textual engagement is deeply physical, emotional, and social and is enacted through fanworks. By developing a theory of critical closeness, this book proposes a methodology for fruitfully putting cognitive science in conversation with fan studies.