This book addresses a major gap in sound art scholarship: the role of audience participation. It offers a survey of participatory sound art from its origins in the historical avant-gardes to the non-institutionalized forms of sonic creativity in contemporary digital culture. In doing so, it proposes an innovative theoretical framework for analysing such phenomena, rooted in Pragmatist aesthetics, affordance theory and postcritique. Combining artwork analyses with qualitative studies, it focuses on three principal aspects of participatory sound art: the ways the materialities of the artworks facilitate and structure the participatory processes; the interplay of the creative agencies of the artists and the participants; and the postcritical approach to sound art's politics, unfolding through the participants' affective gestures. In considering these multiple dimensions, this book contributes to the growing fields of sound studies and participation studies, as well as to curatorial practice regarding sound art and participatory art.