The collection contains material relating to Ireland's research and writings on American theater and personal papers. Forty-nine volumes in the collection contain clippings, printed ephemera, such as playbills, autograph manuscript material, letters, and other material, as well as lists of theatrical performances and lists and profiles of stage performers. The collection features drafts, proofs, and an extra-illustrated version of Ireland's major publication, Records of the New York Stage from 1750 to 1860.