An examination of the mid-seventeenth century maritime battles between Ireland, England, and Scotland, showing them to have had a dramatic impact on the overall conflict. The conflict on the Irish seaboard between the years 1641 and 1653 was not some peripheral theatre in the Wars of the Three Kingdoms. As this first full-length study of the war at sea on the Irish coast from the outbreak of the Ulster rising in 1641 to the surrender of Inishbofin Island, the last major royalist maritime outpost, in April 1653, shows, it was instead the epicentre of naval conflict with important consequences for the nature and outcome of the land conflicts in Ireland and elsewhere. The book provides a clear and comprehensive narrative account of the war at sea, accompanied by careful contextualisation and a full analysis of its Irish, British and European dimensions. This includes the strategic importance of Irish ports, conflict between organised navies and formidable bands of privateers and pirates, the adoption of new naval technologies and tactics and the relationship between conflict onland and sea. Moving beyond traditional accounts of naval campaigns, it integrates warfare at sea into the wider dimension of political and economic developments in Ireland, England and Scotland. Extensive use is made of a wide range of archival material, in particular the High Court of Admiralty papers held in the National Archives at Kew. Dr Elaine Murphy is Lecturer in Maritime/Naval History, Plymouth University.