This book is a stunning achievement. That a biography of a theologian is so engrossing speaks not only to the kind of life that Barth led, but also to the skill and patience of the biographer. What Tietz offers in this book is a comprehensive account of Barth's life and work – the two, of course, being inseparable – that displays him in all his humanity. This is not just a document of what Barth did and where Barth went. It is a remarkable attempt to portray Barth's complex personality – his humour, his temper, his stubbornness, his generosity, his conviction. This all-too-human Barth can often disappear from view behind his gigantic theological corpus. Tietz has done the world of theology a service by pulling him back into the spotlight.

What do we see when she does so? Rarely has a book's subtitle been so appropriate – we see conflict. Sometimes it is the kind of conflict that Barth no doubt revelled in; at other times it is painful conflict, conflict that Barth carried within him as a heavy burden until his death.

The book begins by tracing Barth's family tree (ch. i), before taking in his formative years as a student of theology in Switzerland and Germany (ch. ii). After that we spend a considerable amount of time with Barth the pastor, first in Geneva and then, most famously, in Safenwil, where he would eventually write both editions of his monumental commentary on Romans. After all, it is as a parish pastor that Barth became Barth, so it is instructive to hear of the joys and struggles that he experienced in that vocation.

A biography of Barth is compelled to engage with Barth's writings, since these writings themselves produced as well as followed from much of the conflict that constituted his life. Tietz performs this engagement with skill and clarity. Not only are we given helpful overviews and analyses of some of Barth's most well-known works (chs v and vii tackle the first two editions of the commentary on Romans respectively; ch. xiii is a masterful summary of Church dogmatics), we are also introduced to some of the more obscure texts in Barth's corpus – for example, ‘Des Christen Wehr und Waffen’ (‘The defence and weapons of a Christian’), in which a case is made for violent resistance to Nazi Germany. Tietz does not let us forget that all of Barth's writings, even Church dogmatics, are occasional writings, writings inextricably intertwined with that ‘life in conflict’, even as they desperately seek to do justice to the God who is not bound to any human culture or politics or religion. Indeed, Tietz's portrayal of Barth debunks the idea that he was apolitical, engaged in theological work that was inattentive to ‘practical’ affairs. The lengthiest chapter in the book (ch. x) traces the developments that finally lead to Barth's expulsion from Germany in the 1930s, and highlights the various ways in which he was engaged in resistance to the ideology of National Socialism.

The chapter that deals with the ‘ménage à trois’ (ch. ix) is also deftly handled, and seeks to do justice to all the parties involved. Here as much as anywhere else we get a sense of the conflict that was at the heart of Barth's life. Barth himself could find no way out of it. Having ‘discovered’ his love for Charlotte von Kirschbaum, he was unable – or, better, unwilling – to place a ‘radical distance’ between himself and her, claiming that it was ‘not yet certain’ to him that cutting von Kirschbaum out of his life was ‘necessary for God's will’ (p. 183). It is easy, and perhaps quite right, to adjudge this uncertainty as entirely self-serving (some of Barth's own family members, we are told, were not shy in pointing this out to him). But Tietz's description of the matter gives us insight into its complexity and humanness. Barth, we are shown, is trying (and ultimately failing) to do right by his wife and by the woman he loves, and, ‘under the spell of his own experience’ (p. 409), lives with the pain and guilt that these are not one and the same person.

Barth's esteemed place in the history of theology is not something that transpired after his death. He himself, as well as his friends and family, were aware of his elevated status and therefore elevated responsibility. This sense of duty could easily strike one as hubris, but that is not how Tietz presents it. Instead, Barth comes across as a kind of burdened prophetic figure. While Barth spoke often of the joyous nature of the theological task, one gets the impression that he must have been trying to remind himself of that nature, rather than merely expressing his experience as a theologian. For that experience was, more often than not, a deeply frustrating one, since it tended to isolate Barth from all around him.

Such isolation is perhaps the price one pays for tapping into what Tietz calls the ‘critical potential’ of theology (p. 411). The critic cannot help but be in conflict. But criticism is not the last word. As Tietz helpfully concludes, Barth's theology, as a ‘continuation’ of Reformation theology, is motivated by and concentrated on the joyous news that ‘human beings live from God as the One who faces them, the great You who unconditionally affirms the human being. Held by this You, the human is free’ (p. 411).

Reading Tietz's biography of Barth is, in some respects, an exercise in demythologising. It is easy to look at the multiple volumes of Church dogmatics and to be left in awe at the prodigious mind that produced them. Tietz's book, however, exposes the painful sacrifices that made such work possible – sacrifices not only on the part of Barth, but on the part of those most dear to him. Barth's ‘life in conflict’ left its mark on those around him – for better and for worse.