Letters from 20th century Irish dramatist and memoirist Sean O'Casey, as well as letters from his wife Eileen to an American collector and a letter from Arthur Sinclair to Thomas King Moylan.

Two author's press proof volumes and two playbooks heavily annotated and used by production staff for one of O'Casey's plays. The plays include The Plough and the Stars: A Tragedy in Four Acts; Juno and the Paycock; The Shadow of a Gunman; and Within the Gates: A Play of Four Scenes in a London Park.