A new technique for improvising performances with scripted and memorized lines. The ability to improvise a skilled performance while speaking scripted and memorized lines is of paramount importance to actors working in today's film and television productions, which often allow very little if any rehearsal time. Through his innovative Improvisation Technique, Stephen Book shows the actor how to create a spontaneous performance by applying improvisation to traditional script-acting for film, theater, and television. Book on Acting begins with immediate training in how to improvise. Book's fundamental principle of improvisation is "Acting is doing, and there is always more to do." The actor learns what to do to keep himself in a spontaneous improvisational state. This Improvisation Technique is then applied to exercises with scripted lines, developing sophisticated improvisation skills for enhancing character, emotions, conflict, and agreement as well as improving the actor's audition process. Also included is a unique process for breaking down scripted scenes into improvisation choices. Book on Acting contains film and television scenes in which Book-coached actors, used his Improvisation Technique to create their performances. These scenes, showing the actors' performance choices, demonstrate the use of Improvisation Technique in different genres of acting. Well-known theater and film scenes are included, as well as scenes from such TV shows as Melrose Place, Star Trek: Voyager, L.A. Law, Frasier, and The Practice. Book's Improvisation Technique extends the work of Viola Spolin (author of Improvisation for the Theater). Book was Spolin's student, assistant, representative, and her partner in the Spolin Theater Game Center in Hollywood, where he served as executive director and principal teacher in the 1970s.