The public school district in Biloxi, Mississippi, did not specify which words, exactly, in "To Kill a Mockingbird" are so objectionable that the book was yanked from an eighth-grade reading list last week, 57 years after it published.

"There is some language in the book that makes people uncomfortable," school board vice president Kenny Holloway vaguely told the Sun Herald.

Some language. Maybe it's the same language that concerned a Waukegan, Illinois, school system in 1984; or a middle school principal in North Carolina in 2004; or Virginia's tiny Accomack County School District when it cleansed its libraries of "Mockingbird" last year.

That is: the n-word, which this newspaper also censors — and which Harper Lee pointedly did not when she wrote her Pulitzer Prize-winning novel about racism in the United States.

"We can teach the same lesson with other books," Holloway explained to the Herald last week.

Similarly, we could illustrate the history of U.S. censorship with countless books other than "Mockingbird."

But we'll stick with the 1960 classic — in part because its removal from Biloxi classrooms has launched a protest movement that now includes a U.S. senator and in part because the book is widely celebrated as a condemnation of the racist language it so often offends its readers with.

"What exactly is a n-- lover?" Scout asks her father in "Mockingbird," which is set in 1930s Alabama.

"It's hard to explain," replies the father, a lawyer who spends much of the book defending a black man falsely accused of rape.

"Ignorant, trashy people use it when they think somebody's favoring Negroes over and above themselves," he tells Scout. "It's slipped into usage with some people like ourselves, when they want a common, ugly term to label somebody."

The n-word appears nearly 50 other times throughout "Mockingbird" — almost always in dialogue. The novel won its author a Pulitzer Prize for fiction and "made the values of the civil rights movement — particularly a feeling for the god-awful unfairness of segregation — real for millions," as Michael Gerson once wrote for The Washington Post.

But among those millions of readers, for as long as it has been in print, "Mockingbird" has inspired strong feelings of a different sort in towns and schools and meeting halls across the country.

It was not images of race, but of sex, that caused the first big uproar. The school board of Hanover County, Virginia, banned the book as "immoral literature" in 1966 because the plot centered on rape.

And just like Biloxi today, that school system was widely rebuked — including by the author in a cheeky letter to the Richmond Times-Dispatch.

Lee — who died last year — included a $10 donation with her note "to enroll the Hanover County School Board in any first grade of its choice," she explained.

"What I've heard makes me wonder if any of its members can read," she wrote. "'To Kill a Mockingbird' spells out in words of seldom more than two syllables a code of honor and conduct, Christian in its ethic, that is the heritage of all Southerners."

But the Richmond furor preceded many to come, and they often centered on two syllables in particular.

Garvey Jackson, 13, sat at his desk in Hillsborough, North Carolina, one day in 2004 and listened to his classmates read "Mockingbird" aloud. N-word after n-word.

"To put it simple, I felt uncomfortable," Garvey told the Chapel Hill Herald. His mom did, too.

So the boy made a shirt covered in words from the book — the n-word and its many 1930s-era derivatives — and wore it to English class.

"If it's good enough for the book, it's good enough for the shirt," Garvey told his teacher. He was promptly sent to the principal's office, after which the boy declared that he wanted the book "out of the school system."

Garvey's public protest earned a spot in the American Library Association's very long list of formal efforts to ban "Mockingbird" — from the alleged "psychological damage" it did to the racial integration movement in Warren, Indiana, in 1981, to Accomack County last year, when the mother of a biracial student stood before the school board and pleaded:

"I'm not disputing this is great literature . . . But there is so much racial slurs in there and offensive wording that you can't get past that."

According to the American Library Association, "Mockingbird" was the 21st most-challenged book in the United States for the first decade of the 21st century — coming in behind "Harry Potter" and "Alice" in efforts to yank it from the shelves of schools or public libraries.

"Most of the books that get challenged in America get challenged once or twice," said James LaRue, who directs the library association's office for intellectual freedom.

"But we do have a solid core of classics that endure."

Foremost among those, he said, was the 19th-century "The Adventures of Huckleberry Finn" (with more than 200 n-words between its pages).

"Race has long been a target for censorship in schools," LaRue said. " 'To Kill a Mockingbird' has been challenged pretty much from the beginning — I think because it does such a deft job of capturing a moment in history."

More than 300 formal complaints against books were reported by schools, colleges and public libraries last year, LaRue said — a small fraction of what he suspects is the unreported total.

And this year, he said, was on pace to exceed 2016 in censorship by nearly 20 percent — including the recent uproar over "Mockingbird."

"Silence doesn't make us smarter," LaRue said. "A classic is something that makes us uncomfortable because it talks about things that matter."

Sen. Ben Sasse, R-Neb., might agree. "Our kids are tough enough to read a real book," he chided after the Biloxi school district yanked "Mockingbird" last week.

And while Lee isn't around to defend her work anymore, plenty have taken up the torch.

Arne Duncan, the secretary of education under President Barack Obama, encouraged his Twitter followers to buy copies of the classic for other U.S. classrooms in the wake of Biloxi's decision.

"When school districts remove 'To Kill a Mockingbird' from the reading list, we know we have real problems," Duncan wrote.

If that's true, we always have.