Alexander's book, based on his doctoral dissertation, is concerned with an aspect of Augustine's thought during the period between his conversion and his entry into the ministry of the Catholic Church. This is the period which was subject in the first decades of the last century to debate over the question whether Augustine's conversion had really been to Christianity, or to a form of Neoplatonism. That debate has mercifully been laid to rest; but it has left a backwash of questions over his intellectual and spiritual development down to 395–6, but especially during the years before he assumed ecclesiastical office. It is now generally agreed that in these years Augustine's Christianity was strongly coloured by a form of Platonism current in the circle around Ambrose of Milan.

To any reader of those of his works produced in the five or six years after his conversion it is obvious that ecclesiology played no part, or, eventually, only a very modest part in Augustine's thinking. Nevertheless, if the account he gave later, in his Confessions, of the example given him by the conversion of Marius Victorinus is to be trusted, it is equally obvious that among the things that he had learned in Milan was the truth that the mid fourth-century rhetor had to learn: that walls do indeed make a Christian, that entering through baptism and belonging to an ecclesiastical community was an essential defining feature of being a Christian. Alexander only stresses the importance of humility in Augustine's mind in the example of Victorinus' conversion; he does, however, recognise the decisive importance of his entry into the Church through baptism. Alexander's investigation confronts the problem of Augustine's comparative lack of lack of interest, at any rate for some years, in thinking about the Church. His book is a sustained effort to trace the slow emergence of what can be described as a more or less explicitly formulated theology of the Church in Augustine's works written during this time.

Ten works (or parts of works) fall within these five years, apart from the four Cassiciacum dialogues written before his baptism. Chronology is clearly of crucial importance for Alexander's enterprise. He relies – with some minor reservations – on the received chronology (Bardy, Perler, Hombert) and on J. K. Coyle's important work on De moribus ecclesiae et de moribus Manichaeorum. Two appendices supplement the main argument with tables of word frequencies and Scripture references respectively. Alexander doggedly pursues every scrap of evidence of Augustine's increasing familiarity with the ecclesial community; every hint of Church-related talk is exploited to the fullest extent. The conclusions that emerge from this meticulously detailed enquiry do not surprise. The ‘lack of ecclesial thought or attention’ characteristic of the Cassiciacum dialogues and the works written immediately after his baptism is slowly replaced by attention to some ecclesiological themes, albeit not ‘as objects of attention in themselves’ but indirectly. Slight but numerous, these hints point towards Augustine's growing appreciation of the Church as a subject of reflection. Although Alexander quotes TeSelle's judgement that ‘one could not guess from the writings of Rome and Thagaste that Augustine attended church at all’, he sees Augustine's return to Thagaste and the community he founded there as an important landmark. Rejecting, very reasonably, the view that this community was a `monastery' in any real sense, Alexander devotes a good deal of his discussion to the ascetic tinge – shared with Platonism – that was permanently associated with Augustine's view of the Christian life. In his last year at Thagaste Augustine arrived, so Alexander argues, at his first Christian synthesis in the De vera religione. Although he quotes O'Donnell's statement on the new start that this work represents in Augustine's thought, Alexander is more apt to see it as emerging from the hints that he has unearthed in the preceding works.

Alexander's repeated assertions that Augustine owed nothing to Donatism and knew nothing about it until more than a year after his ordination are oddly arbitrary. The very terms Augustine used from the earliest times to characterise the Catholic Church as spread over the whole world are a clear rebuttal of the Donatist conception of Catholicity. He cannot have failed even as a child to notice that there were two rival communities in every town in Africa, especially in his own Thagaste, both claiming the title. His ecclesiology was set to develop in an anti-Donatist direction from the start. As a whole, however, Alexander's book traces in painstaking detail the minutest symptoms of a largely latent ecclesiology. He asks no new questions and comes up with no new answers, but his book is a conscientious and on the whole successful attempt to fill in the detail of a picture which is familiar only in outline.