The collection is primarily composed of correspondence of Constance de Markievicz. Correspondents include notable artists and musicians, actors, politicians, and authors, such as Robert Brennan, Anna Nordgren, Seumas O'Kelly, Edward Martyn, Tivadar Nachéz, and Jack B. Yeats. The majority of letters contain a discussion of the arts, such as Jack B. Yeats explaining his paintings and criticisms, an expected book deal of Robert Brennan, and an appraisal of Edward Martyn's play, "Grangecolman." Most outgoing correspondence is written to Kathleen Clarke, a fellow Irish revolutionary and founding member of Cumman na mBan and Fianna Fáil.

Also included are typescript biographies and a timeline detailing Markievicz's personal and professional achievements. Materials related to prominent Jewish lawyer Michael Noyk are also included, such as correspondence and a copy of his portrait. The collection also contains assorted ephemera and newspaper clippings related to research about Markievicz, including the 150th anniversary of her birth, her past villa estate in Rathgar, Ireland, and a lock of Markievicz's hair.

The materials in the collection are correspondence unless otherwise noted.