Mark O’Connell was three years old when Malcolm Macarthur – a silken-tongued toff in a bow tie – went on his killing rampage in 1982, and 33 when he was released from prison in 2012. Eight years later, when he began this book, O’Connell describes stalking Macarthur around Dublin in the hope of securing the kind of interview that would cause Ireland’s most famous murderer to ‘tremble in terror and awe at the moral magnitude of his iniquity.