By GUY TREBAY

The treasure hunters left the latesummer light on a recent Sunday to descend into the gloom of the Vault at One Hanson Place in Brooklyn. There, in subterranean chambers, they searched through the folding tables and bins set out by 30 or so vinyl record dealers.

“I buy house and Detroit techno, mainly,” said Matt Arace, a D.J. from Hartford, Connecticut, who was hunting down labels like Kompakt or Minus.

Jeffrey Joe, who teaches high school in Harlem, was “not looking for anything in particular,” simply putting himself in the way of serendipity.

The numbers of vinyl fanatics are hard to measure, but what’s certain is that they are growing, along with vinyl record sales. In 2008, 1.88 million vinyl albums were purchased, more than in any year since Nielsen SoundScan began tracking sales 20 years ago.

That figure may be small compared with the volume of digital downloads during the same period. Yet the people at SoundScan were not alone in noting that a generation raised on MP3 players has lately fallen in love with long-playing records, as well as the outdated technology that was the primary means of playing music at home for the better part of a century.

Mass retailers have taken note and now sell vinyl records and record players . The men’s-wear designer John Varvatos, a collector whose personal stash runs to 15,000 records, was onto vinyl early; his store stocks some of the choicest old records in town.

“Vinyl is the biggest it’s been in 20 years,” Mr. Varvatos said recently.

The Brooklyn vinyl fair on a Sunday in late September was not the largest one around, but it had a distinct flavor of New York. Among the vendors was a senior editor at The Huffington Post Web site; two guys from Other Music, a record store ; a teacher with a sideline selling psychrock record s; and Bill Yawien, a 55-year-old who recently moved from a house to a condo.

“It was time to whittle it down a little,” Mr. Yawien remarked to some browsers perusing his trove of records by Cream, Jimi Hendrix and the Jefferson Airplane and the Mothers of Invention .

It is safe to assume that buyers were also, in some subtle fashion, seeking cultural connections, the kind you can get only from someone like Sal Siggia.

“Someone once called me a culture maven,” Mr. Siggia said. “But I never thought much about what I was collecting. I just knew it was worth saving somehow.”

Almost everything he sold that day, including T-shirts from the nightclub Area and a complete collection of Smiths records, had been acquired not for resale but for personal pleasure. “Everything people bought was my stuff from the ‘80s,” Mr. Siggia said .

Was it tough, Mr. Siggia was asked, to relinquish his treasure, these autobiographical relics?

“No,” he said flatly. “Once I decide to let go, I let go. If I dropped dead tomorrow, all this stuff would be out on Avenue A the next day.”