The first full-length study of playwrights working in the Irish language in the pivotal 1930-80 period. Irish-language theatre has at times been on the fringes of Ireland's cultural landscape, invisible and underground, but its influence can be seen all over the island of Ireland. In this landmark volume, Philip O'Leary analyzes the works of Mairead Ni Ghrada, Seamus O Neill, Eoghan O Tuairisc, Sean O Tuama, and Criostoir O Floinn and discusses the production history of their plays and the critical reception of first productions and major revivals. O'Leary also outlines the beginnings of drama in Irish in the early twentieth century and provides important historical context. The developments in Irish-language theatre since 1980 are also discussed in this important contribution to Irish theatre studies. Using a wide range of sources, O'Leary gives a thorough evaluation of five of the most significant Irish-language playwrights and charts the monumental influence and reach of their work.