A Number is a 2002 English play by Caryl Churchill. The story, set in the near future, is structured around the conflict between a father (Salter) and his sons (Bernard 1, Bernard 2, and Michael Black) – two of whom are clones of the first one. The play addresses the subject of human cloning and identity, especially nature versus nurture. Many critics over the years have lauded A Number, arguing Churchill created a work of significant intellectual depth with effective economy of style. Source: Wikipedia (en)