The Adventures of Huckleberry Finn: Twain's Development of the Theme In Mark Twain's novel, The Adventures of Huckleberry Finn, he uses several different themes. His themes help to portray the meaning and message of the novel. Twain's major theme in the novel is man's inhumanity to man. He develops this theme through the inhumane actions of Pap toward Huck, the dishonesty of the King and the Duke toward the Wilkes girls, and the betrayal of Jim for money by the King and the Duke. Twain uses the inhumane actions of Pap toward Huck to help develop the major theme of hi