Eugene O'Neill's play The Hairy Ape is an expressionistic play. Expressionism began in Germany in the early twentieth century and spread throughout Europe. It was brought to the United States by American scenographer Robert Edmund Jones, who had been studying in Europe. O'Neill wrote the play in 1922, two years after he won the Pulitzer Prize for his realistic play Beyond the Horizon.
Expressionism has a few key elements, all of which are present in O'Neill's play. The most significant element of expressionism is that the world of the play comes from a subjective perspective. In this play, the subjective perspective is that of the powerless and frustrated character Yank, who works shoveling coal in the engine room of a cruise ship and lives in a world controlled by the rich. Another component of expressionism is the simplification of characters into types—in this case, Yank as a mindless worker. Another example of this is the character of Mildred as a spoiled rich woman who is repulsed by the very people she claims to want to help (i.e., Yank). Expressionist plays are also very message-centric. In this way, The Hairy Ape offers a very clear and critical view of social class and the harsh effects of industrialization.