The author of a book critiquing the criminal justice system has an assignment for the state corrections department that just banned his work: Read it.

Chokehold: Policing Black Men” by Paul Butler is an award-winning, critically acclaimed 256-page treatise on the racism in America’s ways of policing, prosecuting and punishing. And if you’re an inmate in an Arizona prison, you won’t be able to find a copy.

The Arizona Department of Corrections banned the book earlier this year, claiming its contents are “detrimental to the safe, secure, and orderly operation” of the state’s penitentiaries. But the policy has prompted both condemnation and threats of legal action, and critics say it amounts to unlawful and mean-spirited censorship.

“This move seems like something out of the 1950s McCarthy era,” Butler told The Washington Post. “Of all things to take away from a prisoner, why would you take away a book?”

Lawmakers, academics and free speech groups agreed with the author: If those who are incarcerated can’t read it, then perhaps those doing the incarcerating should.

“I think it should be required reading,” state Rep. Reginald Bolding (D) said in an interview with The Post. “Whenever the state becomes a sponsor of shielding information, we become just as bad as those we see around the world doing the same thing.”

In one of Christy Lopez’s classes at Georgetown Law, where Butler also teaches, “Chokehold” actually is required reading. Lopez, a former federal civil rights attorney, said she investigated and sued the Arizona Department of Corrections when she was at the Justice Department.

“I can tell you this,” Lopez wrote on Twitter, “they should be requiring all COs to read it instead of prohibiting prisoners from doing so.”

In prison systems from the East Coast to the Southwest, officials have banned books and limited prisoners’ access to them, justifying the restrictions as a way to cut down on drug smuggling or prevent the flow off material that might incite violence. In 1989, the Supreme Court ruled that prisons may prevent prisoners from receiving certain publications — only as long as it’s in the interest of safety. But the results of these policies are often puzzling.

In Texas prisons, where more than 10,000 books are banned, inmates are allowed to read Hitler’s “Mein Kampf” and two other screeds by David Duke, the former grand wizard of the Ku Klux Klan, the Dallas Morning News reported. Meanwhile, Alice Walker’s Pulitzer Prize-winning “The Color Purple” and the “Game of Thrones” comic book series are both banned because of graphic content.

Corrections departments in North Carolina and New Jersey even took aim at one of “Chokehold’s” intellectual forebears, outlawing Michelle Alexander’s “The New Jim Crow” at its facilities. Last year, the American Civil Liberties Union successfully lobbied those states to reverse their bans, and the group’s lawyers are now doing the same in Arizona.

In a letter to the state’s prison director, ACLU attorneys called the policy “unconstitutional” and “fundamentally flawed.”

“The very people who experience extreme racial disparity in incarceration cannot be prohibited from reading a book whose purpose is to examine and educate about that disparity,” they argued.

“Prison officials may not agree with that message, but it’s unconstitutional to ban a book because the government doesn’t like its policy proposals,” ACLU staff attorney Emerson Sykes said in an interview. “The book bans are a symptom of the punitive mind-set that fails to account for the intellectual well-being and growth of those who are incarcerated.”

If the corrections department refuses to rescind the ban, the ACLU has said it may file a lawsuit. Officials at the department did not respond to requests for comment but have told other media they would comment further after reviewing the ACLU’s letter, which was dated May 16. In an email sent to the New Press, Butler’s publisher, the corrections department wrote that it had “determined that your publication described below contains Unauthorized Content.”

Butler said his book and Alexander’s may be threatening for similar, existential reasons.

“They’re books about transformation,” he said. “We didn’t talk about reforming slavery, we talked about abolishing it. We didn’t talk about reforming the old Jim Crow, we talked about abolishing it. I don’t think we should talk about reforming the new Jim Crow, I think we should talk about abolishing it. The ideas are very powerful, but that’s why the First Amendment exists.”

As a former federal prosecutor, Butler said he understands banning books or other materials to protect both inmates and guards.

But, he said, there’s nothing in “Chokehold” that would endanger those inside. On the contrary, he said, he specifically disavows violence, calling it immoral and ineffective. What his book does advocate, though, is a complete overhaul of the justice system, something he said might scare the “prison industrial complex.”

“The ideas in ‘Chokehold’ are dangerous to the status quo; the ideas are dangerous to mass incarceration,” he said. “They are very threatening to white supremacy, and I am proud of the power of those ideas.”

It’s ironic the book is banned in Arizona, Butler said, because the state’s disproportionate rates of arresting and jailing African Americans are stark. As of October 2018, the most recent department data available, nearly 15 percent of Arizona’s prisoners were black — a figure triple the state’s share of black residents.

What’s more, Butler argued, recent research has shown that prisons are often sites of learning for their inmates. A 2013 Rand Corp. study found that pursuing education while incarcerated dramatically decreases an inmate’s chance of committing another crime.

“Why is Arizona standing in the way of that?” Butler asked. “Why isn’t Arizona celebrating the fact that there’s an inmate who wants to read an important book about democracy and America?”