In an era where digital dominates music consumption, 72 percent of vinyl buyers are 35 and under as fans flock to the format's "comforting pops and clicks."

At Amoeba Music, the hangar-size rock 'n' roll Mecca on Los Angeles' Sunset Boulevard, something ­surprising happened just before Christmas in 2013. After a few years of ­moderate growth, vinyl records started flying off the shelves in serious quantities for the first time since CDs took over in the late 1980s. Powered by Daft Punk's Random Access Memories and ­classic rock reissues, LP sales "exploded" that November, ­according to Amoeba GM Rik Sanchez. "It's just continued since -- it's substantial, a really heavy spike," he says. "Having a record in your hand is just way cooler than having a file in your iPod."

It's not just Amoeba -- the stats paint a vivid picture of vinyl's resurgence nationwide. Nationally, sales are higher than at any time since 1990, according to Nielsen Music and RIAA data. The best-selling vinyl LP of 2014, Jack White's Lazaretto, moved 87,000 copies, according to Nielsen Music, nearly doubling Daft Punk's 49,000 in 2013. In the same period, total sales soared 51 percent to 9.2 million. (Vinyl now comprises 6 percent of total physical album sales; indie rock and classic rock LPs are by far the format's best-sellers.) Across the country, at shops from Waterloo Records in Austin to Ear X-tacy in Louisville, Ky., vinyl sections have grown to take over most of the floorspace. Even major chain retailers like Target, Urban Outfitters and Whole Foods, which sells a curated selection of discs ranging from The College Dropout to Amnesiac at select stores, have gotten into the act.

So why, in an age defined by seamless, maximum-convenience experiences like Spotify and iTunes, is a technology that requires users to manually flip a disc over every 20 minutes luring fans back? And just who is driving the progress? Surprisingly, the market skews young. "Early on it was guys like me, the bald-spot-and-ponytail crowd," says Record Store Day co-founder Michael Kurtz of the event, which spearheaded the current boom when it launched in 2008. "Now it has evolved to where the majority of people who come are under the age of 28." Even though fans 35 and under make up 44 percent of the overall music marketplace, according to The NPD Group, they account for 72 percent of vinyl sales, according to MusicWatch. (There's a reason Urban Outfitters stocks all that vinyl.)

As for the appeal, there are at least as many reasons as there are fans. But after speaking to industry experts -- from label heads and major artists to retailers and mastering engineers -- three main trends emerge. There's the desire to listen to music in a more focused way, as opposed to something you put on in the background. There's a craving to collect something physical and tangible at a time when most culture lives as data in the cloud or on a hard drive. And there's the perception that music sounds better (or at least warmer) on vinyl.

For Michael Carney, the Grammy-winning album designer who works with such acts as The Black Keys (drummer Patrick Carney is his brother), 12-inch LPs are the ideal package for an album. With their full-scale artwork and ability to include inserts like posters, CDs and download cards, the LPs are tailored for the band's most hardcore fans. The sleeve for Turn Blue, for instance, has "tipped-on" artwork -- the cover image is printed on the ideal paper and then glued to the cardboard package -- required by the custom-color ink Carney used in his Op Art-inspired design. "Those kinds of subtle details might not be obvious, but the customer picks up on it," he says. "There's this move toward the more boutique or bespoke. I mean, people like talking about what kind of Japanese looms their jeans are made on now."

That idea doesn't just apply to the package -- it also describes the discs themselves, with their delicate grooves painstakingly etched for maximum fidelity. According to Shawn Britton, chief engineer of Mobile Fidelity Sound Lab, vinyl comes closer to capturing the sound of master recordings than CDs (and especially sub-CD-quality digital formats like the 256kbps AAC files iTunes sells). MFSL specializes in audiophile-grade reissues of classic LPs -- lately new versions of Miles Davis' Kind of Blue and Bob Dylan's Blonde on Blonde. "In the studio, we can listen to the same recording on different formats, and I can A/B quickly between them," he says. "What I've found is the higher the resolution, the less fatiguing. If I work on a CD, eventually I have to go outside and listen to the trees for a while. But with vinyl, I can work much longer and not fatigue." (Vinyl's main limitation, according to Britton, is trouble with reproducing certain low-frequency sounds.)

"There's a nostalgic feeling to the whole thing," adds Tower Records founder Russ Solomon. "There's something comforting about the clicks and pops."

During the last few years, as the wave has gained momentum, demand has grown to where it exceeds supply. There are just 16 pressing plants in the United States, ranging from Rainbo Records in Canoga Park, Calif., which produces some 7 million records a year, to smaller operations like Nashville's United, which specializes in trick-colored or scented vinyl increasingly demanded by clients including Jack White's Third Man Records. For the best-selling Lazaretto, White went all out -- among the LP's many Easter eggs are two tracks hidden under the center labels and holograms etched into the disc. "Someone told me when I had my upholstery shop, 'If you just do what you love, people will come and find you,' " White tells Billboard. "That attitude has transferred over to Third Man."

Increasing production isn't simple, though: The equipment used to press records has been out of production for decades, with many of the old machines sold for scrap. As a result, labels looking to get an LP to market have to plan far ahead, booking time at a domestic plant as much as six months in advance or going overseas to factories in the Czech Republic or Holland. It's enough of a bottleneck that at least one indie label, Fat Possum, and some partners opened their own plant -- Memphis Record Pressing -- and are working on cranking out 7,000 units a day. "We're just trying to get it where it plays good, and it looks good, and it's on time," says Fat Possum founder Matthew Johnson. "That alone is a handful."

Anyone wanting to predict whether vinyl is a passing fad or an enduring format could do worse than looking at turntable sales. Crosley, which makes popular entry-level gear (selling, according to the company, "multiple millions" of units a year), has seen record-player sales spike 32 percent from 2013 to 2014 -- the fifth straight year of double-digit growth.

It's a key metric, because fans who invest in the gear tend to buy records. "Once a music fan adopts vinyl, we find that they buy two to three times as many albums as they used to," says Record Store Day's Kurtz. In another sign of vinyl's continued vitality, Record Store Day's organizers get multiple emails weekly from newly opened shops wanting to participate -- and the event has grown into a global phenomenon, with 1,436 outlets participating in 2014, up from 994 in 2010. A virtual cottage industry of books (Amanda Petrusich's 2014 Do Not Sell at Any Price), websites (Analog Planet) and exhibits ("Mingering Mike's Supersonic Greatest Hits," currently at the Smithsonian American Art Museum) lets fans dive deeper into the culture of the format. DJs who helped keep vinyl plants alive through 12-inch singles in the slow days have rediscovered the format, with "vinyl-only" stages popping up at major festivals like New York's Electric Zoo. All of these things are good news for a vinyl superfan like White. "We want kids of this generation and the next generation to lay on the living room floor and look through the liner notes while they're listening to the record," he says. "That's all we can hope for."

This article first appeared in the March 14 issue of Billboard.