If, as Thomas Flanagan has asserted, ‘the importance of John Mitchel's Jail journal to the tradition of Irish separatism has been underestimated’, the appearance of James Quinn's recent short biography of Mitchel is to be welcomed. Indeed, the remarkable thing is that Quinn's was the first book-length biography of Mitchel to be published since 1938. The biographical literature on Mitchel has veered between the hagiographic and the critical before settling, ultimately, into an apparent historiographical indifference. This essay examines Mitchel's biographies, his commemoration in periodical and ephemeral sources, and the development of the historiography of this most ardent republican, concluding that a renewed interest in Mitchel is timely.