Be SpectACTive! is a European project based on audience development, involving organisations working on active spectatorship in contemporary performing arts. Its members are European festivals, theatres, universities and research centres. During four years, the network implemented various actions willing to develop audiences and citizen participation in artistic choices and creation processes, including participatory programming groups, participative residencies, and digital participation. These projects were accompanied by an action research and several practical and theoretical exchanges, including international conferences. This book intends to share the Be SpectACTive! collective adventure, giving a voice to artistic directors, artists, participants and researchers who have been involved in the projects, describing, through case studies and reflections, their successes, limits and perspectives.