Improvisation is a tool for many things: performance training, rehearsal practice, playwriting, therapeutic interaction and somatic discovery. This book opens up the significance of improvisation across cultures, histories and ways of performing our life, offering key insights into the what, the how and the why of performance. It traces the origins of improvisation and its influences, both as a social and political phenomenon and its position in performance training. Including history, theory and practice, this new edition encompasses Theatre and Performance Studies as well as Drama, acknowledging the rapid reconfiguration of these fields in recent years. Its coverage also now extends to improvisation in the USA, cinema, LARPing, street events and the improvising audience, while also looking at improv's relationship to stand-up comedy, jazz, poetry and free movement practices. With an index of exercises and an extensive bibliography, this book is indispensable to students of improvisation.