Car Talk called it quits today. The NPR staple — first broadcast locally 35 years ago on Boston’s WBUR and nationally 25 years ago — will air its last original episode in October. After that, new shows will be produced from the program’s vast archives.

The show is by any measure a success, with 3.3 million weekly listeners on 660 stations, according to NPR spokeswoman Anna Christopher, making it NPR’s top-rated weekend program. While weekday blockbusters Morning Edition and All Things Considered reach far more listeners across five days, Car Talk enjoys the highest listenership by average quarterly hour; that is, “there are more people listening at any one moment to Car Talk than to any [NPR] national program,” Christopher said.

It’s also an object lesson in one powerful way to develop a show, or any creative endeavor, really: organically. Car Talk came into existence by accident and developed its distinctive voice at its own pace. Sometimes, the shows that aren’t focus-grouped and lab-tested and worried-over end up being the decades-long hits. The ones that end up sounding human.

I called up Doug “Bongo Boy” Berman, the show’s longtime executive producer, to understand what makes the show endure. (Berman has a gift for making radio; he also created Wait Wait…Don’t Tell Me!) He said the show was born as something else entirely, in 1977, back when WBUR was a volunteer radio station:

Some guy had a generic call-in show, and he thought it would be a good idea to do something on cars one week. And he invited six area mechanics in to take calls, and Ray thought it was a dumb idea, so he sent Tom. And Tom was a panel of one. He’s the only who showed up. He took calls, and apparently it went well, and the guy said “Hey, can you come back next week?” And he said “Sure, can I bring my brother?” And the following week they came back, and the guy who invited them had been fired and left them a note saying “Hey, good luck, watch your language.”

It would air for a decade before WBUR hired Berman to create a national pilot.

“I think this show benefited from 10 years of benign neglect in a lot of ways,” Berman told me. “They didn’t know what to do, and they weren’t getting paid. And they didn’t think anybody was listening. So they were just themselves.”

Nothing else on the radio sounded like it. The Magliozzi brothers weren’t stentorian or far away — they were right here in your living room. I mean, listen to these guys:

Here’s where another master storyteller enters the picture, Susan Stamberg. In 1987, NPR’s longtime correspondent had just begun hosting a new show called Weekend Edition Sunday. They were asking stations to send in anything that might work well as smaller segments, and they got all kinds of submissions from across the country. I called Stamberg for the story:

There are many versions of this story, but this is my favorite, the one I’m about to tell you: An air check was sent to NPR and it made the rounds. So the news director then was Robert Siegel, his assistant took it in, his then-assistant Jo Anne Wallace, who’s now the general manager of KQED in San Francisco.

Jo Anne listened. She thought these two guys talking about cars might have some potential. She played it for Robert, Robert said, “Well, I don’t know, send it around…” And then it was handed to me, and I gave it to my husband, who’s a big car buff, and he listened and — we’d met in Boston, so there was room for the accent — he listened and he said, “Gee, I don’t know, Susan, I’m not exactly sure.”

And then I listened and I said — this is why it’s my favorite version — “You betcha these guys are fabulous! They’re hilariously funny, everybody loves cars, and even if they don’t, they’re so wonderfully entertaining. And that accent is hilaaaarious. We’ve got to put them on!”…

They were very resistant to the idea because I was going to be working with them. They had had a two-man show for all those years, and here this interloper host was coming in, me, to join because that was what our format was, I sort of took part in everything. But when they heard — and honestly, this is the God’s truth, and I had no idea how important it would be that I had a 1974 Dodge Dart, which is Tom’s all-time favorite car. Slant 6 engine. They were won over!

After about nine months as a five-minute segment, the Magliozzi brothers got their national show.

Although they retire this year, Car Talk will continue airing in re-runs indefinitely. There are 25 years’ worth of archives and 12,500 calls to work with, many of them previously unaired. Berman said everyone on staff at Dewey Cheetham & Howe, the company that produces Car Talk in conjunction with WBUR, will remain employed, including producer Carly Nix, editor David Greene, Russian chauffeur Picov Andropov, butler Mahatma Coat, second-shift meteorologist Claudio Vernight, and wardrobe assistant Joaquin Closet.

“I think their stuff will hold up the same way the Marx Brothers’ does. I think it’s that good. I think people will enjoy it generations from now,” Berman said. “And I think they’ve changed the way people see public radio in America, where it was once seen as exclusive and very serious, I think made it warm and accessible and welcoming. They had a lot to do with that. NPR’s grown tremendously over the last 25 years, but they were at the center of that.”

It’s a sound NPR is always looking to reinvent; in April I wrote about the network’s attempts to create programming that draws in a more diverse audience.

Stamberg agreed: “It made it sound as if all of us did not have Ph.D.’s, which we do not all, but they certainly brought us down to earth.”