Book excerpt: Niklas Frank was just seven years old when his father, Hans Frank, Hitler's legal adviser and Governor General of occupied Poland, was executed at Nuremberg as a Nazi war criminal. Throughout his life, Niklas has attempted to come to terms with the enormity of the crimes his father committed, and this remarkable book traces how after years of research he uncovered the extent of the horror unleashed by the man who was known as the butcher of Poland. The Father is an extraordinary account of a scarred son struggling to comprehend the depravity of the acts that were committed by his father. Whereas other descendants of Hitler's henchmen and co-collaborators have tried to explain or to forget the crimes of their forebears, Niklas's disgust for his father's actions is unremitting. This book is his attempt to seek revenge. Featuring forewords by Philippe Sands and Sir Ian Kershaw, The Father is by turns shocking, twisted and heart-rending; a devastating settling of accounts written by a son addressing his father as he pictures him burning in the eternal fires of hell.