At the last church she attended before dropping out, Julia Duin was not impressed with the service opportunities available to her as a single woman.

She could do child-care work, greet people at the door or join the women in the altar guild. However, since her journalism work required frequent travel, Duin sought more flexible commitments. Perhaps she could play harp before services? Fill an occasional teaching role, using her seminary training or material from her books?

After several frustrating years, she quit going to church.

Soon she discovered that she wasn't alone, which caused the Washington Times religion-beat specialist to do what reporters tend to do. She started listening, reading and connecting dots. What she found was, as one researcher put it, a "spiritual brain drain" out of churches today.

"I found that a lot of people who were leaving were not necessarily new believers. They were the Baby Boomers who had been involved in all of this for 20 years," said Duin, speaking at the recent national Religion Newswriters Association meetings in Washington, D.C. These active, committed laypeople had "been there and done that. ... So you couldn't just say to them, 'Oh just try this. Oh just try that.' "

Many believers, she said, are sad or mad -- or both. "They say, 'Listen ... I've done everything. Now I'm in the middle of a mid-life crisis and I'm not getting any answers.' These are the people who are saying, 'I'm out of here.' "

The result of her research is a new book, "Quitting Church," that pours painful experience over a foundation of troubling statistics.

It's important to stress that Duin -- a longtime family friend -- focused on active churchgoers, not the "backsliders, the slackers and the complainers" most church leaders think would quit.

Also, this is not another volume about the fall of the "seven sisters" of liberal Protestantism -- the Episcopal Church, the United Methodist Church, the Presbyterian Church (U.S.A.), the United Church of Christ, the Evangelical Lutheran Church in America, the American Baptists and the Christian Church (Disciples). In recent decades, their membership totals have declined 20 percent or more -- a trend shaped by falling birthrates, bitter doctrinal fights, an aging population and other factors.

Now, sobering statistics are showing up elsewhere. The Southern Baptist Convention, for example, has seen a steady decline in baptisms. While the nation's largest non-Catholic flock claims 16 million members, Duin noted that its 2007 report indicates that about 6.1 million people regularly attend worship services.

Gallup polls keep showing church attendance hovering at roughly 40 percent of the U.S. population. However, Duin noted that two other studies from 2005 cut that number down to 18 to 20 percent.

What's happening? Duin shows evidence of parallel and even clashing trends. Many people say they're too busy, some are burned out and others are mourning the loss of great churches they knew in their past.

There are paradoxes in this story, too. In recent decades, thriving megachurches have dominated the landscape, offering media-friendly services and chatty sermons in gigantic sanctuaries that give seekers a cushion of anonymity. But in 2007, the influential Willow Creek Community Church near Chicago found that many older members said they are now spiritually "stalled" or "dissatisfied."

Duin is convinced many evangelical churches are also struggling to deal with rising numbers of single adults and single-parent families. In 2005, a University of Virginia researcher found that 32 percent of married men and 38 percent of married women are churchgoers. But only 15 percent of single men and 23 percent of single women go to church.

There's another reality that is hard to put into statistics, said Duin. Many believers have grown tired of quickie services, PowerPoint answers and pop lyrics. Many "quitters" she interviewed were yearning for intimate, down-to-earth churches where pastors and people knew their names. They'd been born again. Now they wanted to know how to face the doubts and pains of daily life. They wanted real spiritual growth.

Many candid believers, said Duin, "are perplexed and disappointed with God" and they found that when they asked tough questions, they "were not getting meaningful answers from their churches. In fact, they were encouraged not to talk about their pain. ?

"The big questions are not going away and the answers can no longer be put off."