After nearly two dozen novels, mostly concerning crimes and court cases, best-selling author John Grisham takes up a non-fiction pen for this true-crime tale, subtitled “Murder and Injustice in a Small Town.” Grisham follows the real-life case of Debra Sue Carter, who was raped and murdered in her Ada, Okla., apartment in 1982. Several years later, Ron Williamson, a down-and-out former ball player, and his passing friend, Dennis Fritz, a school teacher, are charged, tried and convicted of Carter’s death. Williamson is sent to death row; Fritz gets life in prison. As the title suggests, though it should be called “The Innocent Men,” Williamson and Fritz didn’t do the crime. Another man did, which Grisham reveals from the opening pages of this book, but the cops and prosecution ignore this man; ironically, this same man sets into motion the wheels that will lead to the wrongful conviction of Williamson and Fritz. Grisham paints a picture of cops forcing confessions from dreams, of prosecutorial arrogance and malfeasance, of incompetent defense attorneys, and justice that is not so much equitably blind but prejudicially looks the other way. Grisham fans seeking the suspense of his crime and court novels, or the wonderful storytelling of books such as “Bleachers” or “The Last Juror,” won’t find similar thrills here. Grisham presents his facts methodically. It isn’t a volume to stay up until 3 in the morning to finish, but it is a narrative that is engrossing and informative. Regular observers know that justice does grind slowly, though not always efficiently or correctly. With “The Innocent Man,” Grisham reveals many of the American court system’s deficiencies in frightening and disturbing detail.