Literary adaptation is the adapting of a literary source (e.g. a novel, short story, poem) to another genre or medium, such as a film, stage play, or video game. It can also involve adapting the same literary work in the same genre or medium, just for different purposes, e.g. to work with a smaller cast, in a smaller venue (or on the road), or for a different demographic group (such as adapting a story for children). Sometimes the editing of these works without the approval of the author can lead to a court case.