The latest book from veteran O'Neillian Edward L. Shaughnessy, Down the Nights and Down the Days: Eugene O'Neill's Catholic Sensibility examines a major aspect of the playwright's vision: the influence of his Catholic heritage upon his moral imagination. Critics, aware of O'Neill's early renunciation of faith (at age 15), have been inclined to overlook this presence in his work. However, Shaughnessy makes no attempt to reclaim O'Neill for Catholicism.

But Shaughnessy does uncover evidence that O'Neill retained the impress of his Irish Catholic upbringing and acculturation.