How does theatre, one of the most ancient and physical arts, relate to the modern, dynamic technology that is social media? Used daily by many, social media has become one of the main mediums through which we present and perform our lives. In this timely introduction to the revealing relationship between theatre and social media, Patrick Lonergan considers social media as a performance space, analyses how theatre-makers' engagement with social media on and off stage affects elements of theatrical composition and reception, and explores the practical and conceptual implications of audiences interacting with professional productions through social media.