The author of the play Peer Gynt is Henrik Ibsen, a Norwegian playwright who lived from 1828 to 1906. He is considered to be one of the founders of modernism in theatre and is often referred to as the 'father of realism'. His works are known for their exploration of social issues and their focus on the individual's struggle for self-realization. Ibsen wrote many plays, including A Doll's House, Hedda Gabler, and An Enemy of the People. Peer Gynt is one of his most famous works, and it tells the story of a young man's journey of self-discovery.