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.