ST. PETERSBURG — The mystery begins on the top shelf of a section labeled MISC, between JAZZ and LATIN and RAP AND REGGAE.

This is where the St. Petersburg Main Library keeps its Tangerine Dream. Thirteen CDs by the group's founder, Edgar Froese, and another by his son Jerome. Below that, 11 CDs by another member, Klaus Schulze, and more than a dozen by Tangerine Dream, including three box sets. Then, on the next shelf, three dozen more. Below that, another three dozen.

Now, Tangerine Dream is not unknown. They're a pioneering German synthesizer band best known for ambient '80s movie scores like Risky Business and Firestarter. They have no hits, but you could expect to find a CD or two in a well-stocked library.

But this? This is not normal. The library has at least 115 CDs by or relating to Tangerine Dream. That's more Tangerine Dream CDs in one library than David Bowie or Michael Jackson CDs in the entire Pinellas County library system.

Viewed on the racks, from the spine, it just looks insane: More than six feet of shelf space in the city's largest library devoted to an esoteric German band. Why? Who would ever want this much Tangerine Dream? Where is the public value?

Then you pull one off the shelf and flip over the cover. And you spot your first clue to an answer.

• • •

Sharon Hoover used to poke fun at her brother's quirky book collection, filling five floor-to-ceiling bookcases.

"Why did you buy so many books?" Hoover asked him. "My God, you know there is a library."

Paul Bergquist was "Scandinavian, pretty stoic, pretty to-himself," said his sister. But he had eclectic interests. Born in Minneapolis but raised in St. Petersburg, he was a Coast Guard boatswain who later worked in film and TV production. He was also an artist who rebuilt Indian motorcycles, admired the films of Ingmar Bergman and raised English bulldogs and whippets.

And he loved Tangerine Dream. Live albums, box sets, rare singles, he bought them all.

"Paul could listen to Tangerine Dream for hours," said ex-wife Colleen Trickey. "He understood the organic-ness of the creation."

Hoover didn't get it. Maybe their minimalist music suited his dry, contemplative personality.

"I wish I could have asked that," she said. "?'What drew you to this, to have so much of this, to have everything they ever did?' I know I should have asked why. It's the question of, why do we all end up who we are? Why do we keep what we keep?"

She never asked. Not even near the end of his chemotherapy, when they'd take long walks together to Pass-a-Grille and St. Pete Beach, laughing about "what stupid Scandinavians we were," she said. "It's those moments you always remember."

Bergquist died Sept. 14, 2012 at 63. Hoover was the executor of his estate. She went through every box and shelf, sorting out what to do with all this odd stuff.

A chunk of his estate went to the SPCA and Humane Society. Some family military items went to Largo's Armed Forces History Museum. Some artwork went to ZooTampa at Lowry Park. Some genealogical records went to a local Swedish society. Some clothing, housewares and bike parts went to Clearwater's Homeless Empowerment Program. Hoover would occasionally hear back about a homeless person who'd gotten a job thanks in part to her brother's old clothes.

"Things like that do me good," she said.

But his musical obsession, Tangerine Dream. How do you pay something like that forward?

• • •

It's hard to watch art and media go to waste. This is why people collect books for school drives and hawk old VHS tapes for a buck apiece at yard sales.

"I think people have a tendency," said Mika Nelson, director of the St. Petersburg Library System. "They don't want to throw away a book."

Most libraries accept some donated items in good condition. Not everything will make it into circulation, but if an item is popular or uncommon enough, a library will take it off your hands.

"Whatever we can get in good condition that will satisfy the community's needs," she said, "we're going to try to add it."

You might think, in the age of Spotify and other digital services, libraries would have little need for CDs. In fact, Nelson said, their usage rate in St. Petersburg remains high. If her budget allowed, she would probably purchase more.

Hoover knew none of this while scratching her head over what to do with Bergquist's Tangerine Dream CDs. She couldn't imagine anyone would want the entire trove, and wasn't about to list each one on eBay.

Then, while going through a desk, she found it. Her brother's St. Petersburg library card. She couldn't help but chuckle.

I knew it all along.

• • •

So now that Pinellas County library users hold stewardship over what might be the largest public collection of Tangerine Dream music in America, what are they to make of it?

One man who considers it a good point of entry on the band: Jerome Froese, who played with his late father in Tangerine Dream from 1990 to 2006.

"The initial reason that a whole collection now went to a library is a sad one," he said. "On the other hand, it's a great opportunity to get a picture of the complete works from a band who had such a decisive influence on the genre of electronic music."

There are a few rare and collectible titles, including a hard-to-find bonus disc from an expensive 1998 box set that appears to have been autographed by both Froeses. (Today, only a photocopy of the signature remains.) They are not valuable, transplanted from their original packaging into standard library boxes. Their value — the value of any library collection — is more intellectual. With a world of music to be discovered online, a carefully curated physical collection can still be of use to the curious.

"When I was young, I was lucky to be able to listen to music in well-stocked record stores all day long," Froese said. "But generations before only had the opportunity to listen to somewhat more 'special' tunes via friends, or sometimes in a public library."

Lila Denning, the library's acquisitions coordinator, was only "marginally familiar" with Tangerine Dream before the donation. Now her staff knows them, just because the CD collection is so unique.

"I can tell you for sure, they do circulate," she said. "People do place holds on them."

This, Hoover said, would have brought Bergquist the most joy, knowing one of his great loves had been promulgated in some small way. It showed he was right to get that library card long ago.

"I'm at the library all the time," she said, "and I'm constantly telling people, 'Don't you realize everything that goes on at the library? What you can get? What you can do?'?"

It was the library's idea to add a small white sticker to each CD, with a message accented by a clip-art shooting star. Pull one off the shelf, and you can't miss it.

In memory of

Paul C. Bergquist

"A Friend of the Library"

Contact Jay Cridlin at cridlin@tampabay.com or (727) 893-8336. Follow @JayCridlin.