The American Civil Liberties Union is asking New Jersey Department of Corrections to lift an alleged ban of a book that examines the impact of mass incarceration on people of color.

According to the ACLU of New Jersey, at least two New Jersey facilities have banned Michelle Alexander’s book The New Jim Crow: Mass Incarceration in the Age of Colorblindness.

The New York Times bestseller examines the impact of mass incarceration, which the ACLU says disproportionately affects black Americans in New Jersey the most out of any other state.

"For the state burdened with this systemic injustice to prohibit prisoners from reading a book about race and mass incarceration is grossly ironic, misguided, and harmful," ACLU lawyers wrote in a letter to the state’s DOC. "It is also unconstitutional."

The ACLU argues that there is no ban on the book as part of the state’s administrative code, and only found out about the ban after receiving reports from inmates and filing an open records request.

“The DOC’s response indicated that New Jersey State Prison and Southern State Correctional Facility banned the book as a matter of policy,” the ACLU said.

“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 ACLU-New Jersey Executive Director Amol Sinha in a statement. “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.”

ACLU attorneys Tess Borden and Alexander Shalom ask Gary Lanigan, commissioner of the New Jersey Department of Corrections, for answers by Jan. 24.

On Amazon, the book is the top seller in the “discrimination and racism” category.

“With dazzling candor, legal scholar Michelle Alexander argues that ‘we have not ended racial caste in America; we have merely redesigned it.’ By targeting black men through the War on Drugs and decimating communities of color, the U.S. criminal justice system functions as a contemporary system of racial control — relegating millions to a permanent second-class status — even as it formally adheres to the principle of colorblindness,” the book's description reads.