Otto Friedrich Gruppe was a German philosopher, scholar-poet and philologist who served as secretary of the Prussian Academy of Arts in Berlin. Poems by Gruppe were set to music by Johannes Brahms, Richard Strauss, Karl Löwe, Elise Schmezer, and Franz Schreker. He rediscovered the cycle of Latin elegies by the Augustan poet Sulpicia and demonstrated their poetic value.
Otto Abels Harbach, born Otto Abels Hauerbach was an American lyricist and librettist of nearly 50 musical comedies and operettas. Harbach collaborated as lyricist or librettist with many of the leading Broadway composers of the early 20th century, including Jerome Kern, Louis Hirsch, Herbert Stothart, Vincent Youmans, George Gershwin, and Sigmund Romberg. Harbach believed that music, lyrics, and story should be closely connected, and, as Oscar Hammerstein II's mentor, he encouraged Hammerstein to write musicals in this manner. Harbach is considered one of the first great Broadway lyricists, and he helped raise the status of the lyricist in an age more concerned with music, spectacle, and stars. Some of his more famous lyrics are "Smoke Gets in Your Eyes", "Indian Love Call" and "Cuddle up a Little Closer, Lovey Mine".
Otto Hintze was a German historian of public administration. He was Professor of Political, Constitutional, Administrative and Economic History at the University of Berlin. Influenced by Ernst Troeltsch and Max Weber, he emphasized the continuity and rationality of Western institutions.
Otto Holzapfel is a German folklorist and researcher of traditional German folk song. He is a retired professor at the University of Freiburg. His mother tongue is Danish. He studied in Frankfurt am Main; among his subjects were Scandinavian languages and literature with Klaus von See. In 1970 he was appointed curator (archivist) at the German Folk Song Archives in Freiburg, now Center for Popular Culture and Music, University of Freiburg. He led this institute until 1996. He was co-editor of the journal Jahrbuch für Volksliedforschung from 1984 to 1998 and editor of the Studien zur Volksliedforschung. Special topics of Holzapfel are the traditional German folk ballad and the tradition of the German folk song, European mythology and German-Danish genealogy. He has edited several volumes of the standard edition of the traditional German folk ballads Deutsche Volkslieder mit ihren Melodien: Balladen, and he created a system for analyzing German quatrains. Since 2006 he supervises the German song index (Liedverzeichnis')', now online.
