The Rise Of Benedict XVI, by John L Allen

He has followed that with the first book on the election of Joseph Ratzinger. It is a widely informed account of John Paul's last days and the extraordinary weeks that followed. It can also claim authority: Allen has interviewed eight cardinals on condition of anonymity.

How did the conclave produce such an extraordinary result? In Conclave, Allen listed 20 "front runners" and put Ratzinger among "the rest of the field". Towards the end of last year, there was a sudden surge of enthusiasm for a Ratzinger papacy, but even at John Paul's death Allen was having none of it.

The reasons Allen adduced for Ratzinger's rejection were good ones: he was a non-Italian European, too closely identified with John Paul's papacy, with too little pastoral experience, and too right wing. So how did the 78-year-old hardliner from Bavaria swing it in a mere four ballots?

Allen's answer is that something extraordinary happened on the pope's death. The vast effusion of sadness, the influx of millions to view the corpse, the presence of dozens of heads of state at the funeral - all had a profound impact. Before, he writes, observers had theorised about a Third World pope, or a transitional figure after the Wojtyla roller-coaster. But after the funeral, "they now realised they needed a pope... who could reach out, who could inspire and challenge".

Another explanation is possible: Ratzinger simply grasped the conclave by the scruff of the neck. As prefect of the college of cardinals, he ran the show from the funeral on. He knew all the cardinals; he proved he had the energy for the job, and the desire for it. He also benefited from John Paul's reform, by which a candidate eventually needs a simple majority. When it was all over, he went out onto St Peter's balcony with his hands clasped above his head, like Iron Mike after a knock-out.