The Observer reported in 2013 that "Gordon Thomas, a Protestant, was given access to previously unpublished Vatican documents and tracked down victims, priests and others who had not told their stories before" and had uncovered "evidence on Pius XII's wartime efforts to save Jewish refugees".

Other than the Pope himself, Thomas gives accounts of the city's Chief Rabbi, Israel Zolli; the Gestapo Chief Herbert Kappler; the famous Vatican rescuer of Jews and PoWs, Hugh O'Flaherty; the Pope's secretary and housekeeper Sr. Pascalina Lehnert; and the British Ambassador to the Vatican, Sir D'Arcy Osborne.

[1][3] In a review for The Irish Times, Emeritus Professor of History Peter C. Kent wrote that the book is a "good read" and that Thomas' style is journalistic narrative, which centres on the Pope attempting to lead his Church through the "chaos of war" and "provide humanitarian assistance" to its victims and while "unprepared to challenge the perpetrators of these cruelties, he was concerned that the suffering should be contained and lent his secret support and funding to the work of a variety of people who helped Jews to escape the Holocaust and anti-fascist soldiers and politicians to hide from their pursuers.

Fischel wrote that Thomas reveals that the Pope devised a strategy of "silence" in the belief that denunciation would provoke further reprisals against the Jews.

Fischel added this assessment of the topic: "Pius’s 'silence,' however, was deafening during the deportation of Rome’s Jews (let alone the rest of European Jewry) to Auschwitz and other death camps.