Rowan's Rule, By Rupert Shortt

On the cover of this biography of Rowan Williams, the Archbishop of Canterbury's hand frames a face with a slight smile, the eyes looking with candour straight at the reader. What should we deduce from such an image? That it signals a book where the man behind the mitre might be exposed to our gaze?

Rupert Shortt's account is certainly revealing, a comprehensive study that attempts to get to grips with both the character and theology of the man who has been the Church of England's leading cleric for the past six years. Shortt, a former pupil of Williams, has had considerable access and, while this is not an authorised biography, there was a certain co-operation between subject and writer. That has enabled Williams's people to distance him from some of the more tawdry revelations about past girlfriends. Although somewhat embarrassing, they hardly merited the Daily Mail's moniker "babe magnet" to describe the Archbishop.

Rowan's Rule, to a Catholic like me, suggests something monastic. Indeed, there are several instances where Williams, despite being married and the leading Anglican primate, does seem monk-like, with his devotion to a structured prayer life, a love of study and simplicity. But both the Church of England and the wider Anglican Communion have been extremely unruly during his time at the top.

Some of the most interesting material is in Shortt's account of Williams's life before Canterbury. As a child, he was prodigiously clever, studious and pious. His parents were Nonconformists but when the 11-year-old Rowan discovered the High Anglican church of All Saints, Oystermouth, above Swansea where they had moved, he persuaded them to forsake their background for the Book of Common Prayer and the Catholic strand of the Church of England. This is not to say he was without the hint of fun and humour which his many friends attest. Nevertheless, he retained an appetite for solitude. He made his way through Cambridge and Oxford as both student and academic, finishing in 1986 as Lady Margaret Professor of Divinity at Oxford, before embarking upon an episcopal career first in Monmouth and later as archbishop of Wales. This account highlights early incidents where Williams seemed too kindly to deal toughly with those causing conflict. Those traits have not helped in Canterbury. Indeed, his seeming ability to see both sides of an argument has sometimes led both parties in a row to think he agrees with them.

Colleagues also noted an intellectual brilliance, a spiritual maturity, wisdom and artlessness. The difficulty for a cleric like Williams is that the Church today requires guile of the kind that a politician might employ, and that the world tends to judge people in public life, even if they aren't politicians, as if they should behave like them anyway.

Shortt reminds us of the optimism, particularly among liberals, when Williams was appointed in 2002. Here was a man of undoubted gifts, who might well have been a spiritual leader who could speak to the nation on matters of heart and soul. If only it were that simple. As Lord Harries, the former bishop of Oxford, said to him: "God has given you all the gifts, and, as your punishment, he has made you Archbishop of Canterbury".

One issue more than any other has put paid to optimism. Williams's archepiscopate has been mired in controversy over gays from the start. The first indication of turbulence was the row over the appointment of the gay-but-celibate Jeffrey John as bishop of Reading. Uproar led to Williams seemingly losing his nerve and rescinding his choice. Then came the anointing of the openly gay and non-celibate Gene Robinson as bishop of New Hampshire.

To some, this is a dispute between tolerance and bigotry, Christianity's past and its future. To others, this is factionalism between a Western world that always thinks itself superior and a developing world growing in confidence. In the Church itself, this is a fight over tradition and biblical purity, and a Christianity that has absorbed the lessons of psychology. This row has served as a proxy for deeper divisions about diversity, church governance and biblical authority. Shortt's account of this festering dispute, which has taken the Anglican Communion to the brink of schism, benefits not only from its detail but from his analysis. Liberals were optimistic that Williams would be sympathetic to the gay cause but, once in office, he put unity above all else. Whether he will succeed will be the main issue for an updated edition.

In the meantime, Shortt serves Williams well, although at times he seems to suggest that he is too high-minded and, well, too holy to be that successful an Archbishop. The time he gives to others, a generosity which in more "normal" lives would be seen as a major asset, has sometimes not helped someone whose role involves being not only the public face of his church but an administrator too.

General readers will find the theology daunting, while those less interested in the low politics will not be so keen on the chapters on factional fighting. The entire volume, while obviously written with co-operation from the Williams camp, would have benefited from more authoritative verification. What it does show is that, like Thomas More, whom Williams played in a college production of A Man For All Seasons, this is a man of razor-sharp intellect trying to find a way through the ecclesiastical and political mire. The result, like this book, is a bit of a curate's egg.

Catherine Pepinster is editor of 'The Tablet'