Harper Lee’s To Kill a Mockingbird has a long history with censorship. It holds the seventh slot in the American Library Association’s top ten most challenged and banned books list for 2017, and it also appeared on the 2009 and 2011 lists. It has been challenged for the depiction of violence, offensive language, and racism.

To Kill a Mockingbird, which was published in 1960, is told from the perspective of 6-year-old Jean Louise Finch, whose father Atticus defends Tom Robinson, a black man accused of raping a white woman, in court during the Great Depression. Despite proving that Tom is innocent, the jury convicts him of the crime. The book explores themes of racial injustice, gender roles, and the loss of innocence. It has been a perennial bestseller since its release and won the Pulitzer Prize. It was also adapted into an Academy Award-winning film in 1962.

In 2017, To Kill a Mockingbird was removed mid-lesson from 8th grade classrooms in Biloxi, Mississippi, over complaints about language in the book, in particular the use of the N-word. The parent who filed the complaint was concerned about her daughter, who is black, and her classmates’ response to the book, which reportedly included laughter over the use of the slur. The complainant did not ask for the removal of the book, and the actions of school officials appeared to be in violation of the district’s materials reconsideration policy. The district maintained the act wasn’t censorship because the novel remained available in school libraries. After protest from free speech advocates, the book was restored to optional reading lists, but parental permission is required to read it.

In early 2018, To Kill a Mockingbird and Mark Twain’s Adventures of Huckleberry Finn were removed from required reading in the Duluth, Minnesota, school district over the use of racial slurs. The removal wasn’t triggered by a specific challenge in this case, instead resulting from the accumulation of complaints over the course of several years. District teachers were not consulted in the decision. Free expression advocates protested the unilateral removal, calling on the district to include those best positioned to make decisions about educational content in future curricula review.

Find more of ALA OIF’s top ten challenged and banned lists here.