During the early part of his purely literary career a large proportion of Warner's collected writings, which then appeared, were first published in the Atlantic Monthly. But about fourteen years before his death he became closely connected with Harper's Magazine. From May, 1886, to March, 1892, he conducted the Editor's Drawer of that periodical. The month following this last date he succeeded William Dean Howells as the contributor of the Editor's Study. This position he held until July, 1898. The scope of this department was largely expanded after the death of George William Curtis in the summer of 1892, and the consequent discontinuance of the Editor's Easy Chair. Comments upon other topics than those to which his department was originally devoted, especially upon social questions, were made a distinct feature. His editorial connection with the magazine naturally led to his contributing to it numerous articles besides those which were demanded by the requirements of the position he held. Nearly all these, as well as those which appeared in the Atlantic Monthly, are indicated in the bibliographical notes prefixed to the separate works. There were, however, other literary enterprises in which he was concerned; for the calls upon him were numerous, his own appetite for work was insatiable, and his activity was indefatigable. In 1881 he assumed the editorship of the American Men of Letters series. This he opened with his own biography of Washington Irving, the resemblance between whom and himself has been made the subject of frequent remark. Later he became the editor-in-chief of the thirty odd volumes which make up the collection entitled "The World's Best Literature." To this he contributed several articles of his own and carefully allotted and supervised the preparation of a large number of others. The labor he put upon the editing of this collection occupied him a great deal of the time from 1895 to 1898.