"I'm gonna be turning 65 this year," Billy Joel told an audience in March, reminding the crowd that he had a significant birthday coming on May 9. "Most people retire at 65, but noooo! So," he explained, "I need a neck brace to hold my head up."

His loyal concertgoing fans knew better. They knew the "neck brace" he was putting on was actually a harmonica-holder, which meant that he was about to play the song that is the finale of his main set every night nowadays: "Piano Man." Even though it was his very first commercially released single, the tune remains his signature song, any one of dozens of other hits could suffice as his show-closer if not for that obvious shoo-in.

What gives "Piano Man" such enduring power four decades into Joel's 65 years? It's probably not the nation's enduring fondness for piano bars, where lone keyboard players perform cover songs just obtrusively enough to keep the tip jar full but softly enough to not interfere with the business of drinking or light necking. It's in the telling of the tale… and the kind of details mixed in among the metaphors that suggest his reminiscence of life among the barflies might be a true story.

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It is. "All the characters in that song were real people," Joel told a Harvard audience in 1994. "John at the bar was this guy named John — and he was at the bar," he added, pausing for the crowd to chuckle at the exactness of his verisimilitude. "Davy was in the Navy… and probably still is," Joel pointed out, shooting down theories that he renamed the character just to rhyme with a branch of the armed forces.

"And the waitress was actually my first ex-wife… a cocktail waitress while I was playing the piano at this place for a while." That would be Elizabeth Weber, Joel's wife for nine years and manager for five, in his pre-Christie Brinkley days. The "real estate novelist" was a fellow named Paul who seemed to have been working on the great American novel forever while he really split his time between being a realtor and being an alcoholic. "Old man making love to his tonic and gin — OK, a little bit of poetic license there. He wasn't really making love to his tonic and gin, because that could be pretty gross, actually."

And what of the character to whom everyone says, "Man, what are you doing here?"… as in "What's a brilliant future legend and billion-dollar tunesmith like you doing in a dump like this?" Joel has some pretty entertaining answers about that, too. He was slumming, to be sure, but he was also hiding out from the music business while he plotted how to get out of a bad contract.

"I dropped out of sight," Joel recalled in an interview with Alec Baldwin on the actor's MSNBC show. "I had to get out of this horrible deal that I'd signed. I signed away everything — the copyrights, publishing, record royalties, my first child — I gave it all away. And I said, 'I've got to get out of this deal,' and I hid in L.A. and I worked in a piano bar under the name Bill Martin."

In 1971, Joel had released his first solo album, "Cold Spring Harbor," on the Family Productions label. It did not bode well that the album was mastered at the wrong speed. Rather than change the timbre of his voice to match the one on the wrong-playing record, Joel knew he had to move on.

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"I was just so happy to get a record deal, I didn't know what I was signing," Joel told "CBS This Morning." "I didn't really have a lawyer representing me… That's when I moved to the West Coast. And I hid out. I got an attorney, I got an accountant, and I said, 'I'm not gonna give them anything until I get out of this deal.' And to make a living, I worked at a piano bar in the Wilshire district in L.A., the Executive Room." (Although the bar was apparently torn down in the early '80s, a sleuth tracked down a photo of the place in the records of the L.A. Library.)

"Somebody would ask for a song," he told the Harvard audience, "and I didn't know the song from a hole in the wall, but if you play enough in major sevenths, you can make a lot of songs sound like other songs." He then sat at the piano and played the co-eds something that sounded vaguely like "Moon River."