West Side Story is a musical written by Arthur Laurents (book), Leonard Bernstein (music), and Stephen Sondheim (lyrics). The story is based loosely on Shakespeare's Romeo and Juliet, which was, in turn, based on a narrative poem by Arthur Brooke entitled The Tragicall Historye of Romeus and Juliet (1562). Set in Manhattan's Upper West Side, the musical explores the rivalry between two teenage gangs of different ethnic and cultural backgrounds. The young protagonist, Anton ("Tony"), who belon...