In 1945, in the aftermath of liberation, the Soviet military that controlled the field for the former prisoners of Katowice, Poland, asked the first Levi and in Leonardo de Benedetti, his prison companion, to draw up a detailed relationship on the health conditions of the Lager. The result was the "Report on Auschwitz": an extraordinary testimony, one of the first reports on the ever developed extermination fields. The report, published in 1946 in the "Minerva Medica" scientific journal, inaugurates the subsequent work of first legal witness, analyst and writer. In the following four decades, Levi will never stop telling the lager experience in texts of various kinds, for the most part ever collected in volume. From the precending research on the fate of its companions to the deposition for the Eichmann process, from the "letter to the daughter of a fascist who asks the truth" to the articles appeared on specialized newspapers and magazines, "so Fu Auschwitz" is a mosaic of memories and reflections Criticism of the inestimable historical and human value. A collection of testimonies, investigations and insights that, thanks to the consistency, the clarity of the style, to the penalty of the method, give us the first Levi that we have learned to recognize as a classic of our letters.