For the past 19 years, Belle and Sebastian has been on a quest. The purpose of that quest? 

"To make better records," says guitarist and songwriter Stevie Jackson.

Next year marks the beloved Glaswegian band's 20th anniversary, and through all its musical evolutions and lineup changes, it has never wavered in that simple mission. Belle and Sebastian formed when singer Stuart Murdoch and bassist Stuart David, who left the band in 2000, wrote the album Tigermilk in music school, then recruited Jackson and the rest of the members to make the 1996 record. The group quickly followed with If You're Feeling Sinister, which The New York Times called "the band's masterpiece." Over the proceeding seven albums, Belle and Sebastian has refined its quirky melodies and cheeky musings on love, death and disappointment, and established itself as one of indie pop's quintessential acts.

But with this year's Girls in Peacetime Want to Dance, the band surprised a lot of people—including itself.

"I kind of said, for a joke, 'Let's make a disco record,' right from the start, because I play in this disco band back in Glasgow," Jackson says, referring to his '70s cover band, the Disco Sharks. "I was just kind of pushing for that kind of thing. But it's always been there. We've toyed with it in the past."

Where previous B&S albums relied mostly on warm, acoustic instrumentation and lush orchestral arrangements, Girls in Peacetime is built on teetering synths, groovy basslines, funky guitars and steadily shuffling beats. Though Jackson had some experience playing dance music, the electronic production mystified him. So the band brought in Ben H. Allen, whose previous producing credits include albums by CeeLo, Animal Collective and Bombay Bicycle Club.

"It was a bit like making a record with the Wizard of Oz or something," Jackson says. "I really liked it because making this record has been a bit more mysterious to me. On a lot of these albums, I really know what I'm doing. It's quite good to be in a realm where you're uncomfortable and not quite sure." Jackson compares the experience of making Girls In Peacetime to that of Belle and Sebastian's fourth album, 2000's Fold Your Hands Child, You Walk Like a Peasant, which was the product of the group spending years in the studio, recording and re-recording. "It got a bit soul-destroying at times, although I do like the result," he says. "I don't remember having any fun making that at all."

But continuing to challenge itself is exactly what's kept Belle and Sebastian going for close to two decades. The members know how they like to work together—"fast and furious," Jackson says—and remain open to whatever influences any of them have picked up outside the group.

"That's kind of tied into our quest, and one of the good things about being together for 20 years," Jackson says. "There are lots of influences, and as we go along, we've been going deeper into them. In recent times, the electronic thing has come more to the forefront."

Jackson says, in the future, fans might expect to hear more classical influence in the band's sound, or even jazz guitar. But for now, Belle and Sebastian is happy to make whatever feels good, one year at a time.

"Anniversaries are times of reflection and all that," Jackson says. "Naturally, I think that's not a bad thing, but it just seems we go from year to year, and suddenly it's 20. No one told us to stop."