Historians are always torn between writing chronologically or thematically. Here, MacCulloch offers his readers the chance to have their cake and eat it: first, a grand narrative of the Reformation through the 16th and 17th centuries; then, a thematic section treating subjects as varied as witchcraft, idolatry and homosexuality.
It both serves as an introduction to the Reformation, introducing and explaining the key figures and their roles (e.g. Erasmus, Luther, Calvin, Borromeo and St Ignatius...), and as a critique on established ways of thinking.
For MacCulloch, it is the ideas behind the Reformation that are most significant and that must take priority over an interpretation of the Reformation that primarily views it as a contest for power e.g. between the Pope and nascent nation states or as a battle for Europe among key elite families.
Thus, he unashamedly has a chapter on St Augustine's theology since he views interpreting Augustine as so central to the issues. In this, overall, he is very convincing. More than that, he is brilliantly lucid. For example, his explanation of the distinction between Calvin's eucharistic theology as opposed to Luther's or Zwingli's (or the Pope's, of course)(p248ff) is both clear and also sympathetic. (Those five pages have allowed me to think through my own eucharistic theology more than any other article I have ever read, theological or historical.) That said, his intellectualism occasionally leads him to make some odd points: e.g. paraphrased from p83, "If there is one explanation of why the Latin west experienced as reformation and the east did not, it lies in listening to the New Testament in the new voice of Greek (not Latin)." Really? That sounds like the bias of an academic to me.
Furthermore, while this is definitely a balanced account, he nevertheless has his heroes. Reginald Pole, perhaps surprisingly, is one of them and it's a pleasure to have MacCulloch rehabilitate him from his reputation as a historical failure: generally, MacCulloch likes people who do their best to promote inclusivity in the Church, even if they failed to achieve their aims. Similarly, from the Protestant wing, he champions people like Philip of Hesse, sponsor of the Colloquy of Marburgh, who resisted a particular confessionalisation in his territories, but wanted a more open scene.
His other, related bias is to those who championed faith on the margins: such as Juan de Valdes, and the others in the Spirituali movement. Thus, MacCulloch may not have an established bias (as with Eamon Duffy and Catholicism) but that doesn't mean he lacks bias per se.
What he does have, however, is a great ability to empathise with religiosity from both sides of the spectrum. His chapter on "The Spirit of Protestantism?" (p528-33), seeing the potency of the locus on the spirit within the togetherness of the congregation, is a marvellous evocation of how a Reformed spirituality really does exist: it's not just a limping beast, as Duffy for example might imply. Yet he's also able, say, to empathise with the discipline and spirituality of the Jesuit movement (p219ff).
Moreover, he pointedly gives credit where it is due as well as highlighting times of shame: for example, he doesn't exonerate the Spanish Inquisition in any way, but he does credit the way it worked tirelessly to prevent burnings for witchcraft (that raged in northern Europe) because it was so sceptical about the phenomenon.
The chapter on sexuality is perhaps more idiosyncratic: do we really know enough to say that homosexuality "formed a common part of the family lifecycle" (p625) sating sexual needs between adolescence and marriage in one's mid-twenties?
But to pick up on and query such examples is really to pick up on how lively and full of vitality this book is. It fully justifies great praise.
It's very readable (though I found it a bit of a slog in the middle, as he explains the seemingly endless French wars of religion. But that's the nature of the subject, I guess) and full of choice anecdotes.
If you want a first introduction to the Reformation, you might be advised to go to Owen Chadwick's book, because that is half the length, but that doesn't mean you shouldn't miss out on MacCulloch.
"Reformation" is a magnificant work of history, but it's more than that. It's an exploration of human spirituality, of how that is shaped by theology, and then what the consequences are when theological convictions are given real political power and influence.
It's a classic.