Born on July 30 1956, Gänswein grew up in Riedern am Wald, a tiny Bavarian village. He was ordained in 1984 and is a doctor of canon law from Munich University. He came to Rome in 1995 and was quickly on the Vatican fast track. In 1996, the then Cardinal Ratzinger asked him to join his staff, and he became a professor of canon law at the Pontifical University of the Holy Cross, an institution affiliated to the secretive Catholic movement Opus Dei.
Those who know him praise his efficiency and analytical ability. "He understands complicated issues within about 10 seconds and can give a clear and immediate answer," one Vatican source said. Gänswein is, though, more than just an impressive theologian. He is, like the man he serves, extremely conservative. "I think he is very dangerous," Daniel Deckers, the author of a biography of Germany's leading liberal cardinal, Karl Lehmann, said. "He's part of a small but very powerful group within the Catholic church. He will use his power to push Ratzinger in a certain direction.
"Deckers recalls travelling to Rome to meet Gänswein. "He's a good guy. He's very eloquent and can be very charming. But he came right up to me and said: 'Oh, you don't like us.' He referred to himself and Ratzinger as 'us', as if the two of them were an institution.
"With Gänswein as private secretary, there seems little hope that Benedict XVI will offer concessions on issues that alienate many from the Catholic church - the use of condoms, gay relationships or pre-marital sex. "You can forget it," one religious affairs writer said bluntly.
A trusted confidant of the last Pope, who made him a chaplain in 2000, Gänswein has worked as Ratzinger's secretary since 2003, and was one of the few aides allowed to give out press statements on John Paul's condition. In the Vatican, Gänswein and Ratzinger dine together, recently entertaining Princess Gloria von Thurn und Taxis, the German socialite, according to reports in the Italian press. In Cologne last week, Gänswein was never far away from his boss - handing the 78-year-old Pope his reading glasses, or travelling with him on a cruise down the Rhine. He was there, too, when the Pope appeared on a hill beneath a flying saucer-shaped dome, for a vast open-air mass. (In his address to nearly 1 million pilgrims who had spent the night camped out in a muddy field, the Pope reminded the young Catholics that they had to obey all of the church's rules - not just the bits they liked. "That basically means no sex, doesn't it?" German pilgrim Malte Schuburt, 19, pointed out.)
Gänswein's critics even accuse him of turning the Pope into a fashion victim. This summer, Ratzinger and his secretary went on holiday to the papal residence at Castel Gandolfo, near Rome, as well as to the Italian Alps at Valle D'Aosta. While both men were hiking in the hills, the Pope appeared in public wearing a Nike hat, designer Serengeti sunglasses and a Cartier watch. "This is Gänswein's style. It's his handwriting," one religious affairs writer said. "This is something I don't understand."
Gänswein's power derives partly from his place in the Pope's very small personal staff. Benedict's long-time assistant is Ingrid Stampa and he has four women - Carmela, Loredana, Emanuela and Cristina - who do domestic duties. They have taken nun's vows but do not wear habits. Pope Benedict writes everything in German in very small script, and Gänswein is one of the few who can read his writing.
So far, Gänswein does not enjoy the same power as Stanislaw Dziwisz, who spent 40 years at Pope John Paul II's side. Some have even dismissed him as the "Black Forest Adonis". Yet it is Gänswein who decides who gets to see the Pope, and who doesn't. He also protects his boss from the mound of papers on Benedict's desk. "He is the Pope's gatekeeper. This makes him a very powerful man," Deckers said.
It is not surprising, then, that the Pope's private secretary is already beginning to inspire dread in liberal Catholic circles. In Germany, the Catholic church is divided more or less between two figures - the liberal-conservative Cardinal Lehmann, the head of the German archbishop's conference, and the ultra-conservative Cardinal Joachim Meisner, the Archbishop of Cologne. Both men were with the Pope last week. But it is no secret as to which Bishop the Vatican favours. "Gänswein is an opponent of Lehmann," one source in the German Catholic church said. "One of Ratzinger's great weaknesses is that his judgment of people isn't always sufficient. He has a small out-reach."
Just what we need: a pope with a 'small out-reach'...