North Carolina’s prison system on Tuesday dropped its ban on a book about mass incarceration and will review other prohibited books after an objection from the state’s American Civil Liberties Union affiliate.

The decision makes North Carolina the second state this month to announce that it will allow its prisoners to read “The New Jim Crow,” a best-selling book by the civil rights lawyer Michelle Alexander about the connection between racism and mass incarceration.

New Jersey, also prompted by a state A.C.L.U. affiliate, said on Jan. 8 that it would overturn a prohibition that two of its prisons had placed on the book.

North Carolina’s Department of Public Safety, which oversees the state’s correctional facilities, said in a statement Tuesday that its director of prisons, Kenneth Lassiter, had decided to immediately remove “The New Jim Crow” from a list of disapproved publications.