The Hairy Ape is a 1922 expressionist play by American playwright Eugene O'Neill. It is about a beastly, unthinking laborer known as Yank, the protagonist of the play, as he searches for a sense of belonging in a world controlled by the rich. At first, Yank feels secure as he stokes the engines of an ocean liner, and is highly confident in his physical power over the ship's engines and his men. However, when the rich daughter of an industrialist in the steel business refers to him as a "filthy beast", Yank undergoes a crisis of identity and so starts his mental and physical deterioration. In a fight for social belonging, Yank's mental state disintegrates into animalistic, and in the end he is defeated by an ape in which Yank's character has been reflected. The Hairy Ape is a portrayal of the impact industrialization and social class has on the dynamic character Yank.