Two events in 1917 - the Bolshevik revolution in Russia and the apparition of Our Lady of Fatima in Portugal - fixed the battle lines of the twentieth century in the mind of Eugenio Pacelli, later Pope Pius XII. After Hitler gained power in Germany and another world war loomed, the Vatican believed it had to make a choice. Knowing that Communist ideology would outlast Hitler's racism, both Pius XI and Pius XII reluctantly chose the Nazis as the lesser evil. In the balance, Pius XII accepted the genocide of European Jews. At the hub of this terrible dilemma, Pius found guidance in the Christian tradition that by crucifying their Messiah the Jews had forfeited their election as the Chosen People. If Christians were God's new elect, it followed that the interests of the Church came before those of the Jews. The crucial test for Pius came with the roundup of the Jews of Rome in October 1943. Pius's efforts to save the Jews were blunted by the Vatican's desire not to set itself against Hitler. When a thousand Roman Jews were put on a train to Auschwitz, Pius did not protest. In this new book, Michael Phayer, author of The Catholic Church and the Holocaust, 1930-1965, makes use of new material in the U.S. National Archives to shed new light on the actions of the Vatican and of the man whom some have called "Hitler's Pope" while others campaign for his sainthood. The threat of communism to the Church was both ideological and financial. A nationalization of European industry would have bankrupted the Holy See. After the war, Pius was a belligerent Cold War warrior. Nothing demonstrates his fear of communism more than his misguided and unethical attempt to thwart communism in South America by abetting the escape of Nazis and Ustasi war criminals.