New Jersey corrections officials say a bestselling book on mass incarceration and racial discrimination will now be available to inmates at all state correctional facilities, following a ban that had withheld the book from some facilities.

The announcement came on Monday after the state chapter of the American Civil Liberties Union questioned why at least two prisons had banned The New Jim Crow by Michelle Alexander, an acclaimed 2010 book about discrimination against African Americans in the criminal justice system.

The pressure group argued 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 department-wide ban on the book. They also said it is being used as a teaching tool in a state program in which inmates enroll in college-level courses while incarcerated.

Prisons and jails are allowed to ban reading materials based on some concerns, such as security.

“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.”