Mark Twain was greatly influenced by the comic writers of what is called the “Old Southwest”: Tennessee, Alabama, Mississippi, and Arkansas. These writers were most often professional men — doctors, lawyers, and other professions — and often from outside the region, producing comic sketches that were intended for a national audience. They often employed a frame device: a sophisticated, genteel outer narrator who introduces the scene and the setting, followed by an unsophisticated, vernacular narrator who tells his story, in dialect. The sketches included bawdy humor, violence, irreverence, and subversion, of which the genteel outer narrator expresses disapproval. The major writers of Southwestern humor included Augustus Baldwin Longstreet, George Washington Harris, Thomas Bangs Thorpe, and Johnson Jones Hooper, all of whom Samuel Clemens read in his formative years. Many of Twain’s early comic sketches followed the formula of the framed narrative, most notably his first national successful publication, “The Celebrated Jumping Frog of Calaveras County.” Twain’s major achievement was to invert the form by calling into question his role as the genteel outer narrator: the vernacular inner narrator is often celebrated. Twain’s experiments with the form were important in his development as a writer but also in the development of realism.