(CNN) A book that examines the effect of the criminal justice system on black men is reportedly not welcome in Arizona prisons.
The book "Chokehold: Policing Black Men," authored by Georgetown law professor and former federal prosecutor Paul Butler, has been banned by the Arizona Department of Corrections, according to the American Civil Liberties Union.
In a letter sent last week to the department, the ACLU argues that the ban is unconstitutional.
"The ban on 'Chokehold' violates the First Amendment and does nothing to protect the safe and secure operation of correctional facilities," the ACLU wrote in its letter, addressed to Charles Ryan, the department's director.
"Under certain circumstances, it is permissible to prevent incarcerated people from reading materials of their choosing. However, it is unconstitutional to censor a book that educates prisoners on how legal, penal, and other institutions have shaped their own lives and poses no threat to the safety and security of the facility."
The ACLU asks the agency to restore inmates' access to "Chokehold" and to remove it from any lists of banned publications.
Andrew Wilder, a spokesman for the Arizona Department of Corrections, told CNN the department "is reviewing the book and the letter and will be providing a response to the ACLU letter upon completion of its review."
This isn't the first time prisons have censored similar books.
Michelle Alexander's "The New Jim Crow: Mass Incarceration in the Age of Colorblindness," faced bans in North Carolina and New Jersey prisons last year. But prison officials in those states reversed course after the ACLU sent them letters.
In a tweet Butler, the book's author, thanked the ACLU for "fighting the ban on my book."
He told CNN he reached out to the ACLU after his publisher notified him that the ADC had denied an inmate's request to order the book on the grounds that it was "detrimental to the safe, secure, and orderly operation" of its prisons.
Butler said that "ideas are powerful" and that it was a "badge of honor" that prison officials had flagged the book.
But he argued that that "Chokehold" is not dangerous to prison systems because it doesn't promote violence. Butler said he wanted to bring the types of non-violent tactics championed by Rosa Parks and Martin Luther King Jr. into the criminal justice system.
Butler solicited feedback from law professors, prosecutors and police officers for the book. But some of the most valuable insights, he said, came from a workshop with inmates at a prison in Jessup, Maryland.
"They were as good as the law professors," he said.
One chapter the inmates addressed, for instance, focuses on "street law for black men," and doles out practical advice that black men can use to peacefully deescalate situations with law enforcement so that they aren't arrested in the first place.
Many of the inmates said they "wished they had read that before they got arrested," Butler said.
Beyond the practical advice, Butler said that the book contains "serious ideas about what good government is and how democracy should work."
Butler said that's important because many prisoners are of high school or college age and need to be continuing their education so they can be ready to return to society.
"Corrections officers should want to encourage reading," he said.