Music for O'Neill's last play turns on two songs of loss, the Irish famine song, "The Praties Song," and the sickening vaudeville ballad "In the Baggage Coach Ahead." The former, which O'Neill dictated to Dorothy Commins, recalls the potato famines that drove so many Irish from their farms to the United States. Here it serves to underscore the poverty of the Irish heroine, Josie Hogan, and her father.

In the play, O'Neill faced the torturing memory of the circumstances surrounding his mother's death. Accompanied by O'Neill's older brother, Jamie, Ella O'Neill had journeyed to Los Angeles to dispose of property left by her husband. There she suffered a stroke and died. Jamie, an alcoholic who had given up liquor in order to be with and to serve his widowed mother, immediately began to drink again, and on the train bringing his mother's body east found a self-destructive anodyne in booze and the arms of a woman he later called "a blonde pig." The events are retold in the long confessional O'Neill wrote for the character modeled on his brother, Jamie Tyrone. The old sentimental ballad almost inevitably provided the undersong to Jamie's outpouring of guilt and sorrow.