James Stephens' “American Diary” is one of the most important documents of early Fenianism. It uncovers the difficulties facing the movement's founders, and offers an insight into mid nineteenth-century American life and the Irish-American community. It also provides a unique first-hand impression of James Stephens' striking personality. It is one of Stephens' scarce full-length pieces and one of the best written, although it has not previously been published in its entirety.