In the midst of the Second World War, the government of Benito Mussolini collapsed. This dictator had, for a decade, held Italy in a dangerous alliance with Nazi Germany. On September 3rd, 1943, in Cassibile, Sicily, the Italian General Castellano and the American General Eisenhower signed a Treaty in which they illustrated the very harsh conditions of Italy's surrender and its passage alongside the Allies. The vicissitudes of this period led first to the imprisonment of Mussolini, and then to his daring liberation by the Nazis. On Italian territory, two governments, that of General Badoglio and that of the Republic of Salo, led by Mussolini's party, faced each other, while the Allies landed in Sicily and Anzio. In Lazio, the Allies began their action against the Nazi-Fascists who were retreating towards the north of the peninsula. In the meantime, relations between Italy and the Soviet Union resumed, and, in 1944, Pietro Quaroni, the first ambassador after the diplomatic break-up of 1940, was sent to Moscow. The book, through Italian diplomatic documents, reconstructs this delicate historical moment in Italo-Soviet relations in the final act of the Second World War.