This document provides an introduction to improvisational theater. Some key aspects of improv covered are: reacting in the moment without a script, taking suggestions from an audience or referee to improvise scenes or full plays, listening closely to fellow actors and building on their ideas, accepting all proposals rather than saying "no", choosing strong characters and using mime to portray the environment, seeking interactions with other actors, and ensuring the performance is pleasurable for both actors and audience. The goal is collective, energetic improvisation.