A school board’s decision to remove To Kill a Mockingbird from eighth grade curriculums in Biloxi, Mississippi, is the latest in a long line of attempts to ban the Pulitzer Prize-winning novel by Harper Lee. Since its publication in 1960, the novel about a white lawyer’s defense of a Black man against a false rape charge by a white woman has become one of the most frequently challenged books in the U.S.

According to James LaRue, director of American Library Association’s Office for Intellectual Freedom, challenges to the book over the decades have usually cited the book’s strong language, discussion of sexuality and rape, and use of the n-word.

“The most current challenge to it is among the vaguest ones that I’ve ever heard,” he says. The Biloxi School Board “just says it ‘makes people uncomfortable.’” LaRue finds this argument unconvincing, contending “the whole point to classics is they challenge the way we think about things.”

One of the earliest and most prominent challenges was in Hanover County, Virginia, in 1966. In that instance, the school board said it would remove the book from county schools, citing the book’s theme of rape and the charge that the novel was “immoral.”

The board walked back its decision, however, after residents complained about it in letters to local papers. One of the most prominent critics of the decision was Lee herself, who wrote a letter to the editor of the Richmond News Leader. It began: “Recently I have received echoes down this way of the Hanover County School Board’s activities, and what I’ve heard makes me wonder if any of its members can read.”

Into the 1970s and 1980s, school boards and parents continued to challenge the book for its “filthy” or “trashy” content and racial slurs. LaRue says that over time, attempts to ban the book shifted from removing it from school libraries, as was the case in Hanover, to removing the book from school curriculums, as is the case with Biloxi (the city will keep the book in school libraries).

LaRue disagrees with the recent decision, arguing that the book, though imperfect, can spark important discussions among students about racial tolerance—especially in light of the increased targeting of libraries. Over the last year, he says, there have been 36 reports of hate crimes in libraries.

These incidences, he says, “typically include vandalism. Someone is writing graffiti on a library wall, and very very often they are racial epithets and anti-Semitic comments.” In at least two of the hate crimes, perpetrators threatened Muslim women who wear the hijab. “In a couple of cases,” he says, “we had people that destroyed the Quran and ripped it up and shoved it in toilets, that sort of thing.”

Many have denounced Biloxi’s ban by citing, as LaRue does, the book’s message of racial tolerance. Still others have taken a slightly different approach. Writer Kristian Wilson argues that although the novel shouldn’t be banned from schools, its use as a teaching tool should be reassessed.

“Lee’s is not the best book to teach white kids about racism, because it grounds its narrative in the experiences of a white narrator and presents her father as the white savior,” she writes.

Atticus Finch, the father and lawyer at the center of the novel, received a lot of attention in 2015 when Lee’s only other novel, Go Set a Watchman, was originally just a draft and was controversially published several months before her 2016 death, at age 89. In the book, seen as something of a follow-up to To Kill a Mockingbird, the main character Scout is shocked to spy her father at a Ku Klux Klan meeting.

Though many readers were dismayed, scholars have long argued that if you read To Kill a Mockingbird from a racial justice perspective, it’s clear that Atticus’ defense of Tom Robinson, the Black man wrongly accused of rape, doesn’t mean that he favors changing the status quo of segregation. And in fact, his sympathy for the KKK is already present in the first book.

“Way back about nineteen-twenty there was a [local chapter of the] Klan, but it was a political organization more than anything,” Atticus tells his children at one point. When asked if he is a radical, an implicit question about his commitment to civil rights, Atticus says he’s “about as radical as Cotton Tom Heflin”—a white supremacist senator and member of the KKK.

Again, this doesn’t mean that To Kill a Mockingbird shouldn’t be taught in schools. But it does suggest that teachers should encourage their students to think critically about Atticus, not just the men who oppose him.