This collection documents the activities of the Lyric Players Theatre in Belfast. It includes correspondence relating to the operation of the in-house literary magazine, Threshold. Of note is correspondence between editor Mary O'Malley and author John Montague. The collection also contains Ray Rosenfield's collection of the theater's playbills, programs, and publications. Rosenfield was a writer who was a literary correspondent for the Irish Independent and Irish Times and an early mentor of Seamus Heaney.