Angelo Roncalli, Pope John xxiii, was beatified alongside Pope Pius ix in September 2000. The process of declaring someone a saint requires that the corpus of his or her writings be examined for any suspicion of heresy – and despite having been taught by Umberto Benigni, the founder of the Sodalitium Pianum, the young Roncalli had indeed been suspected of modernism. It is the collection of diaries gathered for his beatification that is published here in well over six thousand printed pages, quite apart from the often lengthy introductions.

Before turning to what the diaries tell us, something has to be said about the nature of the enterprise. Kept for the most part in cheap exercise books, the text of Roncalli's notes is apparently not always easy to establish, but is here meticulously edited. Quite apart from the text there are extensive footnotes, both of commentary and of information on the people whom Roncalli encountered in his long life. Lacunae are filled in, abbreviations expanded, idiosyncratic spellings noted, but always observing the detailed apparatus criticus set out at the beginning of each volume. It is an impressive exercise in codicology which will have added many hours to the editing, but one must wonder whether all this effort was entirely necessary. It is for the man behind the text that readers will be searching. As Massimo Faggioli remarks in his introduction to the third volume, through these diaries one can reconstruct the early life of Pope John xxiii ‘with an accuracy and depth that is not to be found with any other pope’ (p. ix).

That is certainly true, but one has to add a caveat which applies above all to Faggioli's volume, Tener da conto: agendine di Bulgaria, 1925–1934. Its title is very precise. Roncalli, now the Vatican's envoy in Sofia, kept remarkably detailed accounts of the money he spent on himself or his staff, how much he spent on coal, for example, or on rail tickets. Though people whom he met in the course of the day are sometimes mentioned, the notes in the diary are extremely brief, which leads one to ask what he thought he was doing when he noted down the day's events and expenditures. At least until he becomes pope, Roncalli's entries are fairly brief, and factual. Opinions rarely intrude. ‘A poor life and a very unhappy one’ he remarks of a widow of his home village for whom, as nuncio in Paris, he offers a mass. But for the most part as a diplomat, and indeed later as patriarch of Venice, he keeps his views to himself. It was an approach that he had developed in Bulgaria, but more especially in Greece (see La mia vita in oriente edited by Valeria Martano in the two substantial tomes which constitute volume iv) where he had to keep himself neutral from the competing communities and their various nationalisms. He was rather more sympathetic to the laicité of the Turkish regime, not least because its modernisation was bringing Turkey more into line with the rest of Europe, than he was with the confessionalism of the Greeks. And when the ex-pat Italian community in Istanbul noisily celebrated their country's victory in Abyssinia, he stayed at home. Not all papal representatives observed such self-denying ordinance. ‘Predecessorum tuorum acta semper laudare juvat, etsi sequi non expediat semper’ he noted on 21 April 1937, quoting a letter of Clement iv.

One is bound to read these volumes conscious of the achievements of Roncalli's pontificate. The expression ‘signs of the times’ with which he is so much identified appears in his writings as early as 1903. It is clear that he was already giving considerable thought to the Church's stance on social issues, influenced in particular by US prelates such as Archbishop John Ireland. As the Vatican's man in Greece he cultivated relations with Christian communities not in communion with Rome. His method was personal, establishing links with individuals, rather than institutional. He found himself at odds with those Vatican dicasteries which had oversight of these regions but which did not, he believed, understand the situation. He was also at odds with the small Latin Church of Greece whose members were all too ready to take advantage of the weakness of the Greek Orthodox Church and proselytise. He strongly disapproved. It was a difficult path to follow, not least because the patriarch of Constantinople was strongly hostile. His affection for Greece was real, and during World War II, apart from facilitating the Vatican's links with the Red Crescent, the first of its kind between Rome and the Muslim world, was much concerned with the lot of the Greeks during the British blockade (cf. vol. iv/2, pp. 167–8). Rather surprisingly, given the otherwise remarkably extensive bibliography cited in the footnotes, I noticed no mention of Owen Chadwick's discussion of the same incident in Britain and the Vatican during the Second World War.

With the liberation of France came his move to Paris (vol. v/1, 2, Anni di Francia, edited by Ėtienne Fouilloux) to replace the papal envoy with whom de Gaulle would have no dealings. He records little or nothing of the politics of Paris, and was frequently elsewhere, travelling the length and breadth of the country on visits that were more pastoral than diplomatic. He showed little interest in the intellectual ferment of the day, whether political or theological, and the diary records no encounter with any of the worker priests. On the other hand it does give account of liturgical ceremonies, which he clearly enjoyed. The same attitudes are displayed once more in volume vi (Pace e vangelo, edited once more in two substantial tomes, by Enrico Galavotti) when he becomes patriarch of Venice and for the first time in his long career has significant pastoral responsibility. He exercised it well. He brought the diocesan minor seminary back to the city from rural exile and reorganised the patriarchate to take account of Venice's shifting population. He was put in place with unusual speed because of the elections of early 1953, during which he was expected to promote the fortunes of the Christian Democrat Party. His Paris diaries begin to reflect an alarm at the spread of Communism: in Venice he opposed the ‘opening to the left’ proposed by the Christian Democrats – rather oddly, given that as pope he was apparently to support it.

Volume vi ends with the conclave, about which he reveals little or nothing beyond his alarm – not his surprise – at being elected. In the final volume, Pater amabilis, the editor Mauro Velati, remarks that the identification of the individual with the papal office had, for the previous half century, been so close that keeping a personal diary was unthinkable. In this as in so much else Roncalli broke the mould, not just in his diary but in maintaining a correspondence with his family. The entries remain brief, very largely a record of whom he met: ‘Admiral Deric [sic., actually Douglas Eric] commander-in-chief of the English Mediterranean fleet, with entourage. Must be a Protestant, but respectful’ (p. 371). His most frequent meetings of course were with members of his curia. After his announcement of the Vatican Council they could be tense – especially with Ottaviani, a long-time friend.

Apart from the first volume, a reprint of Alberto Melloni's 1987 edition of Il giornale dell' anima, there are no bibliographies except for what may be gleaned from the footnotes. Each volume has an index, but only of names. The index to volume ii, Nelle mani di Dio, edited by Lucia Butturini, confuses Umberto Benigni, scourge of modernists, with Mario Benigni, author of several important studies of Pope John, but the otherwise impeccable scholarship of this series is a fine tribute to the late Giuseppe Alberigo, and to the Istituto per le scienze religiose di Bologna which publishes it.