Miller cites the experience of Rob Bell, one of the nation's most popular evangelical pastors.
Bell ignited a firestorm two years ago when he challenged the teaching that only Christians go to heaven in "Love Wins: A Book About Heaven, Hell, and the Fate of Every Person Who Ever Lived."
The book angered many members of Bell's church as well as many in the evangelical establishment. He subsequently resigned.
"Farewell, Rob Bell," one prominent evangelical tweeted.
"It's a tough topic for a pastor," said Miller, a former religion columnist for the Washington Post. "If you get too literal, you can risk sounding too silly. If you don't talk about it, you're evading one of the most important questions about theology and why people come to church."
If pastors do talk about stories of near-death experiences, they can also be seen as implying that conservative doctrine -- only those who confess their faith in Jesus get to heaven, while others suffer eternal damnation -- is wrong, scholars and pastors say.
Many of those who share near-death stories aren't conservative Christians but claim that they, too, have been welcomed by God to heaven.
"Conservative Christians aren't the only ones going to heaven," said Price, "and that makes them mad."
There was a time, though, when the church talked a lot more about the afterlife.
Puritan pastors in the 17th and 18th centuries often preached about heaven, depicting it as an austere, no fuss-place where people could commune with God.
African-American slaves sang spirituals about heaven like "Swing Low, Sweet Chariot." They often depicted it as a place of ultimate payback: Slaves would escape their humiliation and, in some cases, rule over their former masters.
America's fixation with heaven may have peaked around the Civil War. The third most popular book in 18th century America -- behind the Bible and "Uncle Tom's Cabin" -- was "Gates Ajar," written in the wake of the war, Miller says.
The 1868 novel was "The Da Vinci Code" of its day, Miller says. It revolved around a grieving woman who lost her brother in the Civil War. A sympathetic aunt assures her that her brother is waiting in heaven, a bucolic paradise where people eat sumptuous meals, dogs sun themselves on porches and people laugh with their loved ones.
"This was a vision of heaven that was so appealing to hundreds of thousands of people who had lost people in the Civil War," Miller said.
Americans needed heaven because life was so hard: People didn't live long, infant mortality was high, and daily life was filled with hard labor.
"People were having 12 kids, and they would outlive 11 of them," said Smith, author of "Heaven in the American Imagination." "Death was ever-present."
The church eventually stopped talking about heaven, though, for a variety of reasons: the rise of science; the emergence of the Social Gospel, a theology that encouraged churches to create heaven on Earth by fighting for social justice; and the growing affluence of Americans. (After all, who needs heaven when you have a flat-screen TV, a smartphone and endless diversions?)
But then a voice outside the church rekindled Americans' interest in the afterlife. A curious 23-year-old medical student would help make heaven cool again.
The father of near-death experiences
Raymond Moody had been interested in the afterlife long before it was fashionable.
He was raised in a small Georgia town during World War II where death always seemed just around the corner. He constantly heard stories about soldiers who never returned from war. His father was a surgeon who told him stories of bringing back patients from the brink of death. In college, he was enthralled when he read one of the oldest accounts of a near-death experience, a soldier's story told by Socrates in Plato's "Republic."
His fascination with the afterlife was sealed one day when he heard a speaker who would change his life.
The speaker was George Ritchie, a psychiatrist. Moody would say later of Ritchie, "He had that look of someone who had just finished a long session of meditation and didn't have a care in the world."
Moody sat in the back of a fraternity room as Ritchie told his story.
It was December 1943, and Ritchie was in basic training with the U.S. Army at Camp Barkeley, Texas. He contracted pneumonia and was placed in the hospital infirmary, where his temperature spiked to 107. The medical staff piled blankets on top of Ritchie's shivering body, but he was eventually pronounced dead.