TRENTON, N.J. (AP) — New Jersey corrections officials, challenged by a civil rights group, announced Monday that a best-selling book on mass incarceration and racial discrimination that had been banned at two state prisons would now be available to inmates at all state correctional facilities.

The state chapter of the American Civil Liberties Union had sent a letter Monday asking why at least two prisons had banned "The New Jim Crow" by Michelle Alexander.

The group called the ban "ironic, misguided, and harmful." It said the ban amounted to unconstitutional censorship of speech on issues of public concern, which is entitled to special protection under the First Amendment.

Corrections officials noted there was no departmentwide ban on the book. They said the book already was being used as a teaching tool in a state program that requires inmates to enroll in college-level courses while incarcerated.

Prisons and jails are allowed to ban reading materials based on certain concerns, such as security, but the ACLU contends officials can't claim that justification applies in this case. They also note that Texas — which the group says has a 10,000-title list of banned reading materials — not only allows the book but included it on a list of publications the state has affirmatively approved.

"Michelle Alexander's book chronicles how people of color are not just locked in, but locked out of civic life, and New Jersey has exiled them even further by banning this text specifically for them," said Amol Sinha, executive director of New Jersey's ACLU chapter. "The ratios and percentages of mass incarceration play out in terms of human lives. Keeping a book that examines a national tragedy out of the hands of the people mired within it adds insult to injury."