At the time of his death in 1964, Sean O’Casey left a substantial body of disparate writings. His poetry, journalism, short stories, diaries, and his history of the Irish Citizen Army have received scant scholarly attention, but give us important clues about his literary development and his debt to other writers. This chapter examines some of these diverse writings to show how O’Casey experimented with a number of different forms. It also shows how O’Casey remained committed to writing in different genres throughout his life, and the chapter reveals some of the literary touchstones that would inform his non-theatrical writings.