Researching radio broadcasts during the Second World War can be a challenging operation due to the lack of direct and reliable archive material. Firstly, it was very rare to record radio broadcasts; secondly, the radio transcripts of programmes aired during the war are not always available. Radio collections from the first decades of the history of radio and from the Second World War might not be comprehensive for several reasons including bombings; lack of awareness of the importance of radio transcripts as a source of information on cultural propaganda and diplomacy; and underestimation of the impact that radio broadcasts would continue to have at the end of the conflict. In the case of Vatican Radio, there is also the difficulty of inaccessible material such as the ecclesiastical archives. For these reasons there have been to date very few studies of radio broadcasts from Vatican City during the conflict.

La radio del papa. Propaganda e diplomazia nella seconda guerra mondiale by Raffaella Perrin is a successful attempt to investigate the role played by Vatican Radio during the Second World War. The book is divided into five chapters: chapter one talks about the station's birth and evolution; chapter two investigates Vatican Radio during the first year of the conflict; chapter three discusses its diplomatic role and its propaganda during the war; chapter four addresses the issue of the relationship between Vatican Radio's broadcasts and the Shoah; and chapter five focuses on the Allied occupation of Rome and Italy's political reconstruction.

The archives consulted by Raffaella Perrin are mainly transcriptions of radio programmes, written by listeners and held in several European and extra-European countries. The archives include the Monitoring Service of the BBC, created with the aim of monitoring foreign radio broadcasts; the Sonderdienst Seehaus, the main German agency in charge of controlling foreign programmes; the American Foreign Broadcast Intelligence Service; and the archive of the Institut Catholique of Paris, containing Vatican City's programmes in French from 1940 to 1943. The nature of these archives implies that the programmes mirrored the point of view of the listening authorities who summarised and translated radio broadcasts from Vatican City into their own languages. As a consequence, this material can be very different from the original programmes. Nevertheless, these archives are an invaluable source of information otherwise inaccessible.

Vatican Radio was officially opened on 12 February 1931. Guglielmo Marconi was first contacted in 1918 by Pope Benedetto XV's secretary, Pietro Gasparri, but it was only after the promulgation of the Lateran Pacts that the radio station was properly established. After a first phase in which the Church was not sure about the appropriateness of the new medium, Vatican Radio became the voice of Catholic interests around the world and countered anti-religious Soviet and Nazi propaganda. However, Vatican Radio was not intended as the official voice of Vatican City. Only in two instances did it become the official voice of the Vatican State: when extracts from official documents from the pope were read out; and when the radio announcer said ‘we officially communicate’. But the officially neutral role of Vatican City became more problematic during the Second World War, when broadcasts from Vatican Radio could have had an impact on the relationship between the pope and the embassies of the countries at war.

Raffaella Perrin claims that during the war Vatican City used Vatican Radio as a tool to unofficially support the Church's position. For this reason, it is difficult to establish whether Vatican Radio was an independent voice or whether it was influenced by Vatican City. From Perrin's analysis of Vatican Radio it emerges that on the one hand, the programmes mirrored the position of Vatican City, while on the other they gave voice to the positions of several Jesuit broadcasters who worked for the station. It is likely that, with the exception of those cases in which the official neutrality of Vatican City was at risk, the Jesuit broadcasters were free to express their own opinions on the conflict.

In the book there are references to letters sent to Vatican Radio by listeners, but the author does not include a section on the actual impact of the programmes on Catholic listeners, as these letters could not be located. However, this is part of a broader issue rather than a reflection on the limit of Raffaella Perrin's analysis. As recent historiography has pointed out, the evaluation of radio audiences during the Second World War is difficult for several reasons, including the lack of reliable quantitative information on the listeners and the habit of listening to the radio in groups.