At my high school graduation party, a friend who was not a Christian walked up and commented on the music playing over the outdoor speakers at my parents' house.

"Why is it," he asked, "that Christian bands always have the best musicians?"

I was a bit perplexed: The tunes he was hearing belonged to Midtown, a pop-punk quartet whose members, as far as I knew, were not Christian.

I also disagreed with my friend's assessment. I mean, I was a big fan of MxPx and Slick Shoes ... but the best musicians? Hardly. (For evidence, listen to"Rappin for Jesus" by Stephen Wiley.)

Until a few years ago, Christian bands occasionally would have a radio hit or two -- dc Talk and Jars of Clay had their moment, as did Sixpence None the Richer -- and then disappear back into oblivion.

Switchfoot, whose CD a friend of mine picked up in a South Dakota pawn shop during our 2001 road trip around the country (that's a different, longer story), seems to have bucked that trend. Being heard on TV promos and Star 98.7, or whatever the pop rock station is in your town, for years to follow, Switchfoot has been one of the lucky few who have broken through without significantly changing their message, though I would argue they too have watered it down and published one really bad album.

This music is part of the bigger, "parallel universe of Christian pop culture," as Daniel Radosh dubs the industry in his new book "Rapture Ready!" (Radosh's list of the top 10 Christian songs begins with Larry Norman's "Why Don't You Look Into Jesus?")

"Rapture Ready!" details the exploits of a secular New York Jew on a quest to the center of evangelical culture. Radosh visits the International Christian Retail Show, the Holy Land Experience and Stephen Baldwin World; serves as part of the mob calling for Christ's crucifixion in Arkansas' Great Passion Play; and goes backstage with Bibleman, AKA "Batman for Jesus." I'll forgive Radosh for avoiding VeggieTales night at a minor league baseball stadium and the giants who break burning stacks of bricks in Jesus' name.

Radosh intersperses Christian camp with more sober accounts of economics and theology. Chapter 4 focuses on the Bible-publishing business and originally appeared in The New Yorker, and Chapter 5, which, believe it or not, appeared in Playboy, is about pre-millenialism and the "Left Behind" phenomenon.

"In the end," Brian McLaren, author of "A New Kind of Christian," proclaims on the book jacket, "he offers evaluations and insights that might be considered downright prophetic, and compassionate too. No evangelical insider could have done as good a job as Daniel Radosh."

He's definitely more sensitive to things he finds strange than Matt Taibbi. The book has been well-reviewed by Relevant magazine and The Forward, among others. I read through a chunk of it last night and, for some reason, found the style quite similar to A.J. Jacobs' in "The Year of Living Biblically." (Jacobs, possibly not by coincidence, also wrote a review for the book jacket.)

In the intro, Radosh explains that Christian culture is no laughing matter, at least not from a business perspective: It is a $7 billion a year industry.

"At some point," Hanna Rosin wrote for Slate.com, "Radosh asks the obvious question":

Didn't Jesus chase the money changers out of the temple? In other words, isn't there something wrong with so thoroughly commercializing all aspects of faith? For this, the Christian pop-culture industry has a ready answer. Evangelizing and commercializing have much in common. In the "spiritual marketplace" (as it's called), Christianity is a brand that seeks to dominate. Like Coke, it wants to hold onto its followers and also win over new converts. As with advertisers, the most important audience is young people and teenagers, who are generally brand loyalists. Hence, Bibleman and Christian rock are the spiritual equivalent of New Coke. Christian trinkets - a WWJD bracelet, a "God is my DJ" T-shirt - function more like Coca-Cola T-shirts or those cute stuffed polar bears. They telegraph to the community that the wearer is a proud Christian and that this is a cool thing to be - which should, in theory, invite eager curiosity.

This is significant because, according to research by The Barna Group, 61 percent of twentysomethings were "spiritually active" teens but have since lost their religion. Christians leaders see culture as the new channel through which to reach the lost and distracted. Radosh writes:

A less reliable statistic -- but one that has galvanized pastors who believe it reflects what they see in the pews -- is that if current trends continue, only 4 percent of today's Christian teens will be "Bible-believing Christians" as adults.

"Less reliable" is far too generous. That factoid is pure fiction. But, nonetheless, Christian culture can increase the fervency of the faithful, something I saw countless times as a teen at P.O.D. and Dogwood concerts (the latter for which I actually skipped my senior prom). They may not be the best musicians, but their message often carries more weight than typical Christian influencers.

As Radosh relays in the first few words of the book when describing a concert on a rural Kansas airfield:

A lanky teenager made his way out of the crow and ran to where his friends were waiting on the periphery, sweat smearing his thick black eyeliner. "Awesome performance." He grinned broadly. "They prayed like three times in a twenty-minute set."

This article was cross-posted at The God Blog.