This series consists of letters, telegrams and postcards written to and from Parker throughout his long professional life. The series includes correspondence from a number of prominent figures in the late nineteenth and early twentieth century literary and theatrical spheres, including William Archer, Hermann Bahr, J.M. Barrie, Harold Child, John Drew, John Drinkwater, Edouard Dujardin, Charles Frohman, Harry Furniss, Constance Fletcher (pseudonym George Fleming), Marguerite Allotte de le Fuÿe, Alfred Percival Graves, Alexander Hevesi, Laurence Irving, William Wymark Jacobs, Henry Arthur Jones, Rudyard Kipling (half a page of a letter survives), Edward Knoblock, the publishers John Lane and R.G. Longman, Marie Lohr, Lillie Langtry, Percy Macquoid, Richard Mansfield, A.E.W. Mason, Cyril Maude, W.S. Maugham, Justin H. McCarthy, William Millington, Frédéric Mistral, Ernest Newman, Barry Pain, Gilbert Parker, Edward Linley Sambourne, Clement Scott, Arthur Shirley, George R. Sims, May Sinclair, Douglas Sladen, Henry de Vere Stacpoole, Fred Terry, Julia Nielsen Terry, Phyllis Terry, Louis Tiercelin, Maud Tree, Viola Tree, Sir Herbert Beerbohm Tree, Frederick Herbert Trench, Mary A. (Mrs. Humphry) Ward, Herbert Waring, Arthur Waugh, H.G. Wells, and E.S. Willard.