Written “with deep pity and understanding and forgiveness for all the four haunted Tyrones,” Long Day’s Journey into Night may be the greatest American play of the twentieth century. After a career of many dramatic experiments—some successes, some failures—in the last years of his life Eugene O’Neill found his most truthful and artistic voice in an autobiographical work detailing the torment of his own family. It earned him a fourth Pulitzer Prize, awarded posthumously in 1957. In O’Neill’s Tyrone family, James Tyrone resembles his father, James O’Neill, a famous actor known for his role as the Count of Monte Cristo. Mary Tyrone is a thinly disguised portrait of the playwright’s mother, Ella Quinlan O’Neill. The two sons, Jamie and Edmund, are pictures of Eugene’s older brother and the playwright himself.

The play is classically structured, the title appropriate. The events of this four-hour drama are compressed into one day, with the first act occurring at 8:30 in the morning, the two scenes of the second act before and after lunch, the third act at 6:30 in the evening, and the final act at midnight. It tells of the journey shared by the four principal characters through one particular day, but the past is always with them. Like Sophocles’ Oidipous Tyrannos (c. 429 b.c.e.; Oedipus Tyrannus, 1715), it is a play of revelation rather than action.

The Tyrone family is like a single living organism; what affects one affects all. The individuals may be in conflict over their own roles, but they are inextricably bound to one another by love and hate. Hostility is never far from the surface. The Tyrones are well aware of each family member’s vulnerabilities and are skilled in attacking them. Like musical motifs, each person’s flaws are played again and again: Tyrone’s miserliness, Jamie’s profligacy, Edmund’s illness, and, most important, Mary’s dependence on morphine. The drinking problem of the three men is ignored and excused, for the most part, because they share it. At the beginning of the play, Mary is supposedly cured after a stay in a sanatorium. The three men hope for a period of normal life, suppressing their fears regarding her continued health. Concern over Edmund’s illness provides Mary with an excuse to resume her habit, and, as though afflicted with a growing cancer, the family organism quickly deteriorates.

Also just below the surface is the guilt accompanying the question of responsibility for Mary’s addiction. At one time or another Mary accuses each of the men: Tyrone because he hired a quack doctor (that is, a cheaper doctor) who prescribed morphine when she was ill after the birth of Edmund; Jamie because he infected her second baby with measles, and when the baby died, she felt obligated to produce another child; Edmund because his was the difficult birth (her third) that required the medication. Unwilling to accept the burden of blame consciously, the men nonetheless are never free of the guilty roles imposed on them. Mary appears to be a helpless victim, overwhelmed by the vicissitudes of life and the insensitivity of the men around her. From another perspective, Mary is a self-involved child, infusing her husband and sons with guilt, demanding sympathy and consideration, and avoiding reality and the responsibility for her own plight. From either point of view, Mary Tyrone is the catalyst for the family’s long journey into a night of sorrow.

The style of Long Day’s Journey into Night is realistic; the set that O’Neill describes is an exact replica of the O’Neill summer home in New London, Connecticut, with its living room and dining room behind,...