Brent Humphreys for TIME Rob Bell

As part of a series on peacemaking, in late 2007, Pastor Rob Bell's Mars Hill Bible Church put on an art exhibit about the search for peace in a broken world. It was just the kind of avant-garde project that had helped power Mars Hill's growth (the Michigan church attracts 7,000 people each Sunday) as a nontraditional congregation that emphasizes discussion rather than dogmatic teaching. An artist in the show had included a quotation from Mohandas Gandhi. Hardly a controversial touch, one would have thought. But one would have been wrong.

A visitor to the exhibit had stuck a note next to the Gandhi quotation: "Reality check: He's in hell." Bell was struck. (Vote on Rob Bell's influence in the 2011 TIME 100 poll.)

Really? he recalls thinking.

Gandhi's in hell?

He is?

We have confirmation of this?

Somebody knows this?

Without a doubt?

And that somebody decided to take on the responsibility of letting the rest of us know?

So begins Bell's controversial new best seller, Love Wins: A Book About Heaven, Hell, and the Fate of Every Person Who Ever Lived. Works by Evangelical Christian pastors tend to be pious or at least on theological message. The standard Christian view of salvation through the death and resurrection of Jesus of Nazareth is summed up in the Gospel of John, which promises "eternal life" to "whosoever believeth in Him." Traditionally, the key is the acknowledgment that Jesus is the Son of God, who, in the words of the ancient creed, "for us and for our salvation came down from heaven ... and was made man." In the Evangelical ethos, one either accepts this and goes to heaven or refuses and goes to hell. (See 10 surprising facts about the world's oldest Bible.)

Bell, a tall, 40-year-old son of a Michigan federal judge, begs to differ. He suggests that the redemptive work of Jesus may be universal  meaning that, as his book's subtitle puts it, "every person who ever lived" could have a place in heaven, whatever that turns out to be. Such a simple premise, but with Easter at hand, this slim, lively book has ignited a new holy war in Christian circles and beyond. When word of Love Wins reached the Internet, one conservative Evangelical pastor, John Piper, tweeted, "Farewell Rob Bell," unilaterally attempting to evict Bell from the Evangelical community. R. Albert Mohler Jr., president of the Southern Baptist Theological Seminary, says Bell's book is "theologically disastrous. Any of us should be concerned when a matter of theological importance is played with in a subversive way." In North Carolina, a young pastor was fired by his church for endorsing the book. (See TIME's photoessay "A Brief History of Hell.")

The traditionalist reaction is understandable, for Bell's arguments about heaven and hell raise doubts about the core of the Evangelical worldview, changing the common understanding of salvation so much that Christianity becomes more of an ethical habit of mind than a faith based on divine revelation. "When you adopt universalism and erase the distinction between the church and the world," says Mohler, "then you don't need the church, and you don't need Christ, and you don't need the cross. This is the tragedy of nonjudgmental mainline liberalism, and it's Rob Bell's tragedy in this book too."

Particularly galling to conservative Christian critics is that Love Wins is not an attack from outside the walls of the Evangelical city but a mutiny from within  a rebellion led by a charismatic, popular and savvy pastor with a following. Is Bell's Christianity  less judgmental, more fluid, open to questioning the most ancient of assumptions  on an inexorable rise? "I have long wondered if there is a massive shift coming in what it means to be a Christian," Bell says. "Something new is in the air."