This dissertation examines the intersection of theatre and society of post-Emergency Ireland through a methodological assessment of social, performative and archival memory. It identifies a group of new Irish plays and practitioners of the period which have been neglected within Irish theatre historiography and foregrounds their importance to the critical understanding of modern Irish theatre in performance and production. These works challenged the boundaries and authorities of both traditional Irish society and also theatre production. Key figures addressed include John Murphy, Carolyn Swift, J.P. Donleavy, Phyllis Ryan, Mary Manning, Edna O’Brien and Hugh Leonard. Through theoretical examination of newly released and digitised archival sources and evidence, such as the Abbey Theatre Digital Archive and theatre collections of NUI Galway, the Pike Theatre papers of Trinity College Dublin, the Brian Friel papers, among others at the National Library of Ireland, Dublin, the evidence assessed constitutes an alternative dramatic narrative. Privately held papers, such as of J.P. Donleavy and of Carolyn Swift, expand our knowledge of central events and practitioners which cumulatively account for a recovery of modern Irish theatre and performance and of its archival memory. By drawing on theorists in interdisciplinary fields, traversing debates of sociology, cultural studies, postcolonial studies, memory studies, and theatre and performance studies, this dissertation address the dichotomy between memory and absence and examines reasons as to why and how these works were excluded from wider theatrical historical narratives. The plays and practitioners here studied questioned and documented a movement towards establishing a radical and modern dramatic expression of Ireland.