This Companion examines the manifold interactions between Irish literature and the periodical press since the nineteenth century. The thirty original contributions map a highly diverse Irish and international magazine landscape that has played a crucial role in fostering, mediating, circulating and translating Irish poetry and prose. By bringing new archival material to bear on canonical writers such as Emily Lawless, Mary Lavin, John McGahern and James Joyce, this book showcases cutting-edge research situated at the crossroads of Irish studies, periodical criticism and the digital humanities. It offers a variegated view of the different agents in transnational periodical networks, investigating the role of authors, editors, publishers and readers in Ireland, as well as considering the circulation of Irish writers in British and American publications. It also recovers forgotten voices by providing the first comprehensive critical accounts of little magazines including A Celtic Christmas, Honest Ulsterman, Kilkenny Magazine, Broadsheet, The Dubliner and Surge. Altogether, The Edinburgh Companion to Irish Literature and Periodical Culture demonstrates the pivotal role of periodicals in the codification of genres and the formation of an Irish literary canon.