EVERY JOURNALIST LOVES A scoop. But when Vittorio Messori learned that he had been chosen by the Vatican to conduct an exclusive television interview with Pope John Paul II last year, the Italian writer was concerned. Messori composed 20 questions that he submitted to the pontiff, but when the interview was canceled because of other papal commitments, Messori felt relieved. "I was very happy the interview was not done," says Messori, 53, a regular contributor to the Italian monthly Jesus. "I had no experience in television, so I was risking making the Pope look bad."

Now that he has helped His Holiness pull off the publishing miracle of the year, though, Messori has reason to rejoice. Intrigued by Messori's questions, John Paul answered them in writing.

"You have asked me questions," noted the Pope in a letter, "therefore you have a right to responses." The result, Crossing the Threshold of Hope (Knopf)—229 pages of reflections on personal and theological matters—has made the 74-year-old pontiff one of the world's best-selling authors. Published in 38 countries on Oct. 20, the book quickly sold 500,000 copies in the U.S. and knocked Faye Resnick's Nicole Brown Simpson from the top of The New York Times's best-seller list.

Some critics say the book is a triumph of marketing over merit. And even a sympathetic reader like Notre Dame theology professor Fr. Richard McBrien predicts that Crossing will be one of the year's most widely unread books. "It is very dense," he says.

A handsome gold-trim dust jacket and a modest $20 price only partly explain the phenomenal sales of the book, for which the Pope received a $7 million advance, to be given to charity. Messori, a lay Catholic who refuses to divulge his cut—"I did it as a service of faith to the Pope," he says—gives all credit to the author. "He writes not as a man who talks only about dogma," he says, "but as a man who gives place to his feelings. Here is a man of the heart."