Improvisational theatre, often called improvisation or improv, is the form of theatre, often comedy, in which most or all of what is performed is unplanned or unscripted, created spontaneously by the performers. In its purest form, the dialogue, action, story, and characters are created collaboratively by the players as the improvisation unfolds in present time, without use of an already prepared, written script.
Improvisational theatre exists in performance as a range of styles of improvisational comedy as well as some non-comedic theatrical performances. It is sometimes used in film and television, both to develop characters and scripts and occasionally as part of the final product.
Improvisational techniques are often used extensively in drama programs to train actors for stage, film, and television and can be an important part of the rehearsal process. However, the skills and processes of improvisation are also used outside the context of performing arts. This practice, known as applied improvisation, is used in classrooms as an educational tool and in businesses as a way to develop communication skills, creative problem solving, and supportive team-work abilities that are used by improvisational, ensemble players. It is sometimes used in psychotherapy as a tool to gain insight into a person's thoughts, feelings, and relationships.
The earliest well-documented use of improvisational theatre in Western history is found in the Atellan Farce of 391 BC. From the 16th to the 18th centuries, commedia dell'arte performers improvised based on a broad outline in the streets of Italy. In the 1890s, theatrical theorists and directors such as the Russian Konstantin Stanislavski and the French Jacques Copeau, founders of two major streams of acting theory, both heavily utilized improvisation in acting training and rehearsal.
Modern theatrical improvisation games began as drama exercises for children, which were a staple of drama education in the early 20th century thanks in part to the progressive education movement initiated by John Dewey in 1916.