From a teacher's perspective, the Adventures of Huckleberry Finn can be a challenging text for numerous reasons. First off, there's the widespread use of the "N-word," which was commonly used in Huck Finn's society. In addition, some take issue with the novel's portrayal of Jim, the intelligent but uneducated runaway slave. 

Mark Twain's use of vernacular can be difficult as well—especially for ELL or other students reading below their grade level—and Twain’s complex language may be difficult for students at many levels, even without the challenge of the vernacular. Due to its controversial language and Twain's satirical approach to serious topics like religion and racism, Huck Finn has been banned time and again since its publication in 1885.