In recent years, the wall between "contemporary Christian music" and the mainstream pop world has begun to crumble. CCM, as it's called today, sprouted up in the 1970s as an alternative for the faithful to make hip, modern musical statements while remaining aloof from a mainstream rock culture whose dedication to decadence was too much at odds with the call of Christ. Christian artists and fans alike sought to be "in the world, but not of it," and made statements like "our rock is not their rock." But many in CCM admit that Christian music has always followed the creative lead of the mainstream, maintaining a safe distance by always keeping their sound a few seasons behind the cutting edge. The most successful Christian pop has been a kinder, gentler version of the trends that give mainstream pop its snap and crackle: soft rock, "alternative," even rap music tweaked with Christian lyrics and references to the Almighty that are anything but subtle. Being derivative, if anything, helped CCM's standing among young Christians, who suddenly had something to crank up on the stereo like their mainstream counterparts. The growing number of teen fans, in turn, got the attention of mainstream entertainment companies. By the early 1990s, most of the big secular corporations like EMI, Warner and Sony had gobbled up major CCM record companies or established outposts of their own in Nashville, the capital of Christian music. Soon afterward, Christian music's biggest stars mounted cross-over bids-Amy Grant with her 1991 hit "Baby, Baby," followed by her former keyboard player, Michael W. Smith, with "Place in This World." Sandi Patty, meanwhile, began popping up on the "Tonight Show" singing patriotic songs. These decidedly nonreligious forays were dutifully covered by the mainstream media, but Grant and Smith's mainstream moment was short-lived.These days, there's a new crossover happening. Relatively unknown Christian bands, like Jars of Clay and Sixpence None the Richer have had stealth mainstream hits, taking their Christian spiritual themes and distinctive sound with them into the mainstream and to the top of the charts before anyone knew who they were and what they stood for. Jars of Clay's breakthrough single, "Flood"-full of imagery from the story of Noah-came in 1996, barely a year after they had established themselves in in the Christian market. The single got healthy play on college radio, then flipped onto top-40 stations, pushing their album to double-platinum sales. Sixpence's Grammy-nominated "Kiss Me," has been one of mainstream's biggest hits this year. With each success in the mainstream world, CCM's committed fans wonder, is crossover going to change our music? CCM, a sometimes regressive industry, where conservative thinking is a source of pride, isn't likely to prostrate itself to produce acts modeled on Jars and Sixpence. But something new is clearly afoot down in Nashville, and insiders have become used to asking, Who will be next to cross-over?