Alt-country group matures with fourth album 'Mirage Rock'.

Things are good for Band of Horses. The South Carolina alt-country quintet's third album, "Infinite Arms", was nominated for a 2010 Grammy Award and debuted at No. 7 on the Billboard 200 -- a personal best. Though it's too early to break out the Champagne, advance buzz on the highly anticipated follow-up, "Mirage Rock" (Sept. 18, Columbia/Brown/Fat Possum), is similarly high.

But none of that is enough to stop singer/guitarist Ben Bridwell from having the occasional vision of an untimely demise.

"Honestly, after every album I always feel like 'Well, we had a good run,'" he says. "I still feel that way. If it all burns to the ground on Sept. 19, I'll just feel extremely fortunate to have made it as far as we have."

Given the group's expanding fan base, Bridwell likely has nothing to worry about. Still, he never would've imagined that the band he started in 2004 would have a top 10 album or embark on a cross-country tour with Willie Nelson, as it will in October.

"Hell, no," Bridwell replies when asked if he ever predicted the rock stardom he now enjoys. "Not then, and not now. It's always been a surprisingly positive experience that we've been lucky enough to keep growing."

For third album "Infinite Arms", which has sold 202,000 copies, according to Nielsen SoundScan, the band pushed itself to the limit, paying for the recording costs without the backing of a label or producer. The group tested a new approach to songwriting as well, with all members joining Bridwell in the creative process for the first time. On "Mirage Rock", not only did the collaborative writing continue, but everything else also went more smoothly.

"The waters have calmed a bit," Bridwell says. While recording "Infinite Arms", "we were in flux with labels, we were in flux with funding and also just in flux personally. There were a lot of loose ends. This time, things seemed more adult, more easy and more fun."

To facilitate the process, the band teamed with legendary producer Glyn Johns -- a Rock and Roll Hall of Fame inductee honored for his work with the Beatles, the Who and Led Zeppelin, among others -- who encouraged the group to record live with minimal overdubbing. The result: an album that sounds remarkably self-assured and unaffected. If Band of Horses has been feeling the pressure of its own success, "Mirage Rock" doesn't show it.

To promote the album, Columbia hosted 60 listening sessions around the country in which limited vinyl test pressings were given to fans. The label also partnered with indie digital retailer Insound to put on a free release-day show in Brooklyn, exclusively accessible to those who preordered the album through the site. Fans who buy a deluxe digital version will also get a large cache of video content documenting the recording sessions.

On Sept. 8, the band played the iTunes Festival in London with Jack White, and will head back overseas for a headlining run after supporting Nelson's Railroad Revival tour in October.

The Johns sessions produced more than 60 songs and, though he's not sure yet, Bridwell believes the unused tracks may find a way into a subsequent release. "There were some that got cast to the side that we still really liked," he says. "We're at least planning on doing something with those, if not rerecording them. We'd like to get on it again as soon as possible."

Of course, "everybody says that when they have an album coming out," Bridwell adds with a touch of cynicism. "And then reality smacks you in the ass."