The literary, historical, and linguistic confluence that characterized the Irish Sea region in the pre-modern period is reflected in the interdisciplinarity of these new research essays, centered on the literatures, languages, and histories of the Irish-Sea communities of the Middle Ages, much of which is still evoked in contemporary culture. The contributors to this collection dive deep into the rich historical record, heroic literature, and story lore of the medieval communities ringing the Irish Sea, with case studies that encompass Manx, Irish, Scandinavian, Welsh, and English traditions. Manannán, the famous travelling Celtic divinity who supposedly claimed the Isle of Man as his home, mingles here with his mythical, legendary, and historical neighbors, whose impact on our image and understanding of the pre-modern cultures of the Northern Atlantic has persisted down through the centuries.