How does O'Neill use allusion in the play, Long Day’s Journey into Night?

Although the drama is not rich in allusions to public events of the time, it does use references to several writers and often includes parts of poems and character references and lines from dramatic works woven into the dialogue. While the furniture in the living room is both sparse and shabby, its two bookcases are filled with volumes of writers past and present, carefully named by O'Neill in his stage directions and mentioned in the dialogue. Tyrone's preference is for Shakespeare, who is often quoted, while Edmund's is for more modern writers and philosophers, like Nietzsche, Dowson, Marx, Baudelaire, and Swinburne, writers that his father finds gloomy, morally repugnant, or anarchistic. Jamie, too, has read his share of literature. In the final act, it is he who quotes several lines from Swinburne's "A Leave Taking" in choric counterpoint to Mary's painful monologue.

Allusion is also made to the famous American actor, Edwin Booth. It is a point of great pride for Tyrone that he had once acted on stage with Booth, who thought highly of Tyrone's skill. But the memory is painful, for Tyrone is plagued by the belief that he traded his talent short for easy money.