It would seem as if the former cardinal Joseph Ratzinger has it in for Scottish writer J.K. Rowling and her young world of sorcery and witchcraft. Even before his papal incarnation, he was busy warning readers to steer clear of the imaginative world they so love on the grounds that it contains too much black magic.

And now to add insult to injury, his own books have gone and knocked the latest Harry Potter book from top place in a German book chart.

While the book, Harry Potter and the Half-Blood Prince, is not due for publication until July, fans are so fanatical that they reserved copies well in advance.

But the German branch of the online book retailer Amazon said the Pope's theological preachings have commandeered the first three places in its list of top 10 bestselling books.

At number one is Salt of the Earth: Christianity and the Catholic Church at the End of the Millennium, a book of Ratzinger's interview with German journalist Peter Seewald, followed in second place by Values in Time of Upheaval, and the self-explanatory Introduction to Christianity.

Master Potter has thus been relegated to fourth place, but with a further four Ratzinger titles in the top 10, just how long he can hang on in there remains to be seen.

Knuckle-wrapping for conspiracy thriller

J.K. Rowling is not the only author to incur the wrath of the Catholic Church whilst simultaneously being affected by its sudden surge in popularity. US author Dan Brown's conspiracy thriller, The Da Vinci Code, which was recently named book of the year at the British Book Awards, has also come under fire from the Vatican.

Cardinal Tarcisio Bertone, the Archbishop of Genoa, was appointed by the Vatican to deny what it says are lies, distortions and mistakes in Brown's bestseller. The book is based on the idea that the church long concealed the fact that Jesus married former prostitute, Mary Magdalene and that she bore him a child.

Bertone said the book is filled with absurd and vulgar falsifications which are a clear attempt to discredit the church. Whatever the case, the book has been a massive success, selling more than 25 million copies in 45 languages worldwide.

But whether it can weather the storm being created by the pope's more purist works remains to be seen. The climb in their popularity on the US Amazon site is slower than that on its German subsidiary, but seven of the pontiff's titles are already in the top 25.

All this theological excitement is big business for a number of German publishers who are working round the clock to keep up with the unexpected demand. Books by and about the former Cardinal had sold out in Germany within just hours of his election and new print runs -- complete with photos of Pope Benedict XVI in his papal robes -- are in the tens of thousands, massively exceeding the original runs.

It's nothing short of a publisher's paradise, and for the time being at least, there is no sign of waning interest.