On the New York Times' best-seller list is an allegorical tale aimed at disenchanted Christians.
The Shack, written by an unknown William Paul Young, is also on the Top 10 on Amazon.com, No. 1 in religious fiction in Publisher's Weekly, and the No. 1 trade paperback fiction at Barnes & Noble bookstores. It is rare for a piece of Christian fiction to sell 2 million copies.
Mr Young, a 53-year-old small-time businessman, turned celebrity overnight: He has been interviewed on TV chat shows, and reportedly has several film offers.
Americans are certainly among the more religious people in the world. A poll showed 85 per cent of Americans saying religion is an important element of their lives, with some 70 per cent stating they want their president to be a person of faith.
No surprise then, that both Senators Barack Obama and John McCain found it worth their while to spend a Saturday evening taking questions from an evangelical pastor who may change their political fate.
Mr McCain grasped the chance to speak loud and clear on the matter of his faith. He has always shied away from public discussions on what he considers his private matter. But this time, the logic was compelling. Pastor Rick Warren's evangelical followers are widely believed to have swung President George W Bush's re-election in 2004, delivering the crucial edge in a swing state like Ohio. That, at a time when public unhappiness with the Iraq war was expected to help Senator John Kerry win.
For Mr Obama, who has never declined to talk about his faith, it was an opening to speak with an audience that traditionally votes for the Republican candidate but is believed to be considering a Democrat as its interests expand beyond moral issues like abortion to social ones like poverty.
Mr Warren's one-on-one dialogue, first with Mr Obama and then with Mr McCain, crystallised the differences between the two.
Asked about abortion, and when a baby begins to have human rights: Mr Obama passed, saying he was pro-choice but understood that there was a moral dimension to the decision.
He said: "I think that whether you're looking at it from a theological perspective or a scientific perspective, answering that question with specificity is above my pay grade."
Mr McCain said: "From the moment of conception... I will be a pro-life president and this presidency will have pro-life policies."
Asked about moral failures, both personal and America's: Mr Obama referred to his experimental use of drugs in his youth.
He also said: "Americans' greatest moral failure in my lifetime has been that we still don't abide by that basic precept in Matthew that whatever you do for the least of my brothers, you do for me."
Mr McCain said his unsuccessful first marriage was his biggest moral failure.
He added: "America's greatest moral failure has been throughout our existence, perhaps we have not devoted ourselves to causes greater than our self interest." He criticised President George W. Bush, saying the country took the wrong attitude after the September 11 terrorist attacks - when Mr. Bush asked people to boost the economy by shopping. Mr McCain said: "I think after 9/11, my friends, instead of telling people to go shopping or take a trip, we should have told people to join the Peace Corps, AmeriCorps or the military."
Asked whether evil existed and how to address it - whether to ignore it, negotiate with it, contain it or defeat it: both men said evil existed. But Mr Obama said that only God could defeat evil, while Mr McCain was unambiguous: "Defeat it."
Asked about their most gut-wrenching decisions: Mr Obama said his was to oppose the Iraq war, a minority position to take at the time.
Mr McCain recalled the time he was a prisoner of war in Vietnam and was offered an early release, but decided to forego the opportunity in favour of another cellmate who had been captured earlier.
Going by the frequency of applause alone, the crowd-pleaser of the evening was Mr McCain.
Presidential faith
Bhagyashree Garekar on why religion is a pull for Obama and McCain.