The subject was difficult and risky: choose one of the worst criminals against humanity that the Earth has ever worn, the commander of the Auschwitz-Birkenau camp, Rudolf Hoess, and based on the answers provided by the applicant during his trial in Nuremberg, try to reconstruct the path that could have done that this man has become a monster. The book is, in part, a novel and for a second, a historical essay. The result is quite impressive and offers an experience of the most outstanding literature. The author's thread - and somehow his thesis to explain the life of Rudolf Hoess (Lang in the novel) - Lang is the duty which is attached at a young age. This, among other, I appreciate the book is that the whole is facing this idea of duty, resulted most often in the SS Lang as blind obedience to military orders; no digression, no side stories in addition to the main, no unnecessary complication either: under the sign of duty, Lang path is linear; it starts with obedience to the father, culminating - so to speak - with the most monstrous form that is: a leading role in the Jewish genocide. With great precision, Robert Merle Lang described as a rather neutral individual, without apparent feelings, is recognizing himself as devoid of sensuality, paradoxically without hatred, violent course, by the result of his actions, but not by an impulse that the dominate. A cold monster, not conceiving to refuse orders given to him and considering his action as that of a technician; he said addressing these judges: "You see, I was thinking of the Jews in terms of units, not in terms of people I focused on the technical side of my task." (p. 363). Previously in charge of finding a method for removing the body, he also said, with the look of a Taylorist its productivity target: "To be honest, I did not like much the pits The process seemed rude, primitive. unworthy of a great industrial nation. I was aware, opting for furnaces, choose a more modern solution "(p. 298). In an efficient text, no frills, probably to remind the technician coldness of the main character, Merle contributes considerably to the explanation of the worst horror that humanity has known. It warns us, not against the duty itself, which would make little sense, but a duty to service purposes contrary to human or, put another way, it reminds us that any kind duty must be subject to the fundamental duty of respect for the man.