They've been performing their own special take on the American songbook for thirty-eight years and counting.
"People haven't stayed married as long as you all have been together," correspondent Michelle Miller noted.
"It's amazing, isn't it?" said group member Cheryl Bentyne.
The places they've been, the things they've done! They've played clubs and concert halls. They've done commercials. And they've won eight Grammy Awards.
Their first was for 1980's "Birdland," which remains their most popular song.
But whatever they do, wherever they do it, it's always with that signature sound: four-part harmony, tight and precise.
"Well, I sing the melody most of the time in the harmony, so that's tough," said Bentyne. "People think it's easy, but it's not."
Tim Hauser, Janis Siegel and Alan Paul have been around from the start. Cheryl Bentyne is the newbie - she signed on in 1978.
"It's not easy to stay in tune with the band and then, you know, my partner is following me in tune," said Bentyne. "If I go off, we're in big trouble.
"But why do you think Manhattan Transfer works as well now as it did nearly forty years ago?" asked Miller.
"People see in us something that they wish there was more of in the world, which is harmony," said Siegel. "And no matter how technologically advanced the music business becomes, I think people will always still want to hear the sound of the human voice, especially raised in harmony."
They've harmonized with gospel and all kinds of jazz, including vocalese where they improvise to instruments like trombones and saxophones and add new lyrics.
"What you want to do is really emanate the emotions, the feeling that was there," said Alan Paul.
But what may be their favorite genre is do-wop - inner city rhythm and blues.
Tim Hauser grew up on it in the Fifties: "I started studying and I got it after a while, and the more I got it, the larger it grew inside of me."
"It just filled you up?"Miller asked.
"Yeah. You stay with it long enough, you get it, because the soul, the dirt is in the music. It's there."
The Manhattan Transfer nearly never made it at all. Their big break came in 1974 when legendary Atlantic Records producer Ahmet Ertegun came to a club to have a listen.
Three years ago, not long before his death, Ertegun recalled what happened next: "I'll tell you, I got them together after the show in a room and I said, 'What can I tell you? You've given me one of the biggest thrills I've had, hearing a new group I've never heard before.'"
They joined the greats in the Atlantic Records Hall of Fame, artists like Ray Charles, Aretha Franklin, Led Zeppelin and The Rolling Stones.
"This is not a group about making hit records; this is a group about making great music, and that's what's wonderful about them," said Ertegun.
The tune "Operator" was their first Atlantic hit.
Hauser said he knew the song had legs the day he first heard the Friendly Brothers' version back at Villanova University in Philadelphia.
"When I played that record, I said 'This is a hit record,' so I just geeked it," Hauser said.
"Yeah. I took it home," Hauser said.
"You stole it?" Miller asked.
"Yeah! And then I just put it away and I said, 'Some day I'm going to make this record, man, because that's a hit. I believed it."
There have been some two dozen albums since, their latest - "The Chick Corea Songbook" - out this past September. Still, the group isn't exactly a household name.
But there are plenty of true believers:
"I saw them twice in one week in the Palladium and it was wonderful," said one man.
"I have great ears - I mean, how they can pick up those harmonies!" said one woman fan. "You can't go wrong with people like this out there listening," said another. "Makes it all worthwhile, really."
For Transfer fans - and for the Transfer themselves.
"How was it you've been able to remain relevant?" Miller asked.
"We're the real deal, you know?" said Hauser. "I mean, I certainly don't rely on my glamour, you know? And we're obviously not chasing trends, that's pretty obvious. I mean, we stick to what we've always been."
For thirty-eight years and counting.