Mark Twain's classic, Adventures of Huckleberry Finn, has been under scrutiny for the use of language since it was first published in 1884. It continues to be one of the most challenged books in the United States. In 1885, the Concord Public Library banned the book for its "coarse language." Critics deemed Twain's use of slang as demeaning and damaging. One reviewer called it "the veriest trash more suited to the slums than to intelligent, respectable people." The Brooklyn Public Library banned the book in 1905 for the use of the word "sweat" (instead of perspiration) and for saying, "Huck not only itched but scratched." Twain fired back by saying, "Censorship is telling a man he can't have a steak just because a baby can't chew it." Although the "n" word appears 200+ times in the book, it didn't initially cause much controversy. More recently Adventures of Huckleberry Finn has been banned or challenged for racial slurs.
In 2011 NewSouth published a sanitized version of the book by replacing the word "nigger" with "slave" and the word "injun" with "Indian." An English professor at Auburn University at Montgomery proposed the idea to the publisher because he felt the pervasive use of the slurs made it more difficult for students to read the book. In an introduction to the new edition he wrote, “even at the level of college and graduate school, students are capable of resenting textual encounters with this racial appellative.”
You can read the complete, Adventures of Huckleberry Finn, here, made possible by Project Guttenburg.