Eugene Gladstone O'Neill, born on October 16, 1888, and died on November 27, 1953, was an eminent American playwright. His poetically titled plays were pioneers in introducing into the U.S. the drama techniques of realism, a movement previously associated with the likes of Russian playwright Anton Chekhov, Norwegian playwright Henrik Ibsen, and Swedish playwright August Strindberg. The tragedy Long Day's Journey into Night ranks among the finest U.S. plays of the 20th century, alongside Tennessee Williams's A Streetcar Named Desire and Arthur Miller's Death of a Salesman. Notably, O'Neill was awarded the 1936 Nobel Prize in Literature and is distinguished as the only playwright to have won four Pulitzer Prizes for Drama.

O'Neill's plays were revolutionary for their time, being among the first to incorporate speeches in American English vernacular and to feature characters on the fringes of society. These characters often engage in depraved behavior and struggle to maintain their hopes and aspirations, only to ultimately succumb to disillusionment and despair. Despite his prolific output, O'Neill wrote very few comedies, with Ah, Wilderness! being the most notable exception. Nearly all his other plays are marked by a significant degree of tragedy and personal pessimism.