As a group, evangelical Christians are some of the most formidable book-buyers in America. In recent years, they’ve elevated titles like Rick Warren’s The Purpose Driven Life, Joel Osteen’s Your Best Life Now, and the apocalyptic Left Behind thrillers—none soaked in mainstream critical acclaim—to the top of best-seller lists. Warren and Osteen both run slick, franchised mega-ministries; the terrifyingly cheerful Osteen describes himself as a “life coach.” The Left Behind books, with their depictions of end-times chaos, go relatively light on the Gospels’ more touchy-feely dimensions.

Young makes an extremely unlikely addition to that company. His book has a rough, homemade quality—Papa speaks in unconvincing pseudo-slang, for instance—and its overall message is one of capital-L Love. The Shack depicts the Trinity as a free-flowing system of relationships bound by love rather than a formula that can be figured out through the Warren-and-Osteen brand of self-help. Young’s wisecracking Papa and her mystical sidekicks don’t want a culture war; they just want to hang out with Mack.

All religions are trying to appease an angry God. People are realizing that an angry God doesn’t work. People are looking for something that calls for some personal authenticity.

Perhaps most boldly, The Shack essentially argues that a relationship with God can be found outside the boundaries of formal religion. All of Young’s characters, including the immortal ones, take a skeptical view of organized faith. I ask Young if he goes to church. For the only time during our meeting, I catch a wary glint in his eye. “Do you mean, am I a member of a particular religious institution?” he says. “No. Do I show up in religious institutions all the time? Yes. Usually by invitation. Am I part of a community of people who try to live their faith and discover what love is? Yes. That’s what I consider church. The church is people.”

It’s easy to see why that might give some Christians pause. Even so, The Shack’s most passionate fans can be found in some of the most conservative precincts of American faith, where the book is subject to endless debate on evangelical blogs and is read en masse by congregations. I ask Young why he thinks that is. “A lot of people are just tired of religion,” he says. “Religion can’t heal us. All religions, as institutions, are trying to appease an angry God. People are realizing that an angry God doesn’t work. People are looking for something that calls for some personal authenticity. What I think this book provides for people is a look at conversations between people who care about each other.”

Young deploys a laugh line at Whipple Creek: “Didn’t everyone grow up among cannibals?”

When he was 10 months old, Young’s Canadian parents moved him to remote Papua New Guinea, where they joined a band of missionaries, the Christian and Missionary Alliance, determined to introduce Christianity to several “Stone Age” tribes known collectively as the Dani. At the time the Young family arrived, in the mid-1950s, the tribes practiced spirit worship and internecine warfare. As depicted by the lurid 1962 book Cannibal Valley, by Russell Hitt, Dani tribes often devoured the bodies of slain warriors from rival factions. (Hitt’s book includes a photo of Paul Young’s father baptizing a Dani in a lagoon.)