It didn't record or come with a speaker. But it was sociable: Two could listen at once through a pair of headphone jacks, and an orange button called the Hotline let you talk over the music.
Since then, 340 million of the suckers - including CD and digital players - have been sold. Walkman has worked its way into the Oxford English Dictionary. And street etiquette has never been the same.
It was already called Walkman when I'd saved enough (about $540 in today's money) to buy one that winter, needing tunes for a road trip to Washington, and I remember walking the mall to the new wave splash of the Beat, the Sinceros and Split Enz.
For a mix-tape obsessive, this was like sprouting wings. Countless new soundtracks beckoned. I made running tapes, sunning tapes, sauntering tapes, strutting tapes. It provided groove for the quotidian, put joy in waiting. I was no longer prisoner of Donna Summer or Molly Hatchet on the radio.
Masaru Ibuka wasn't thinking of a revolution when he asked his Sony underlings for something to take with him on a long flight to the States. The Sony co-founder was thinking it would be nice to hear classical music.
Engineers in the tape-recorder division tinkered with the Pressman, a portable, monaural device popular with journalists, removing its speaker and its ability to record. According to Sony's corporate history, Ibuka called from America: The batteries had run out and the tapes they had given him were blank.
Chairman Akio Morita is credited with championing the new player, sensing how young people would want to have their music with them all the time.
At Morita's insistence, the original Walkman wasn't an isolating machine. The Hotline let someone interrupt your music if necessary. A demonstration film showed a couple listening to a Walkman while riding a tandem bike. It was Sony's quaint notion of sharing music.
Executives had worried that their product would diminish the pleasure people got from listening to music together.
The orange button lasted all of two years. By the introduction of the 1981 model, the Hotline was history.
Michael Schiffer, author of "The Portable Radio in American Life," is an archeologist at the University of Arizona, and when he looks at something, he starts thinking about what happened before.
He doesn't blame the Walkman for a decline of Western civilization. Not entirely.
It was just another step, like the transistor radio, something he loved as a kid, in private, because it let him listen to Dodgers games when he was supposed to be sleeping.
"The Walkman was critical in altering the rules of being with other people," Schiffer says. "People thought it was rude to listen to music in public. Now our standards have eroded to the route we've gone down with cell phones, which is to sanction rudeness. We are losing sociability."
He's right, but wait - I'm getting an idea: We could start with Keith Richards' singing "Losing My Touch," then go to Generation X's "Dancing With Myself," into Syd Straw's "Listening to Elvis" and Glenn Miller's "With My Head in the Clouds" . . .