Throughout his lifetime of book collecting, P. S. O'Hegarty's commitment to Irish nationalism indelibly colored his acquisitions. Believing that the collector should follow his or her interests rather than the vagaries of the market, he built one of Ireland's largest private collections of Irish literature and history. As a bibliographer he helped to establish the canon of the works of figures in the Irish literary renaissance and of those who were active in the struggle for Irish independence. Not only as a collector and bibliographer but also as a journalist, activist, and civil servant, he was an advocate of a strong Irish culture.

The son of John and Katherine Hallahan Hegarty, Patrick Sarsfield O'Hegarty was born in Carrignavar, County Cork, on 29 December 1879. His namesake, Patrick Sarsfield, was an Irish Catholic soldier and popular hero in the late-seventeenth-century war of James II against the English and one of the...