Even prior to extended quarantines, lockdowns, and self-isolation, it was hard to imagine life without the electronic escapes of noise-cancelling earbuds, smartphones, and tablets. Today, it seems impossible. Of course, there was most certainly a before and after, a point around which the cultural gravity of our plugged-in-yet-tuned-out modern lives shifted. Its name is Walkman, and it was invented, in Japan, in 1979. After the Walkman arrived on American shores, in June of 1980, under the temporary name of Soundabout, our days would never be the same.

Up to this point, music was primarily a shared experience: families huddling around furniture-sized Philcos; teens blasting tunes from automobiles or sock-hopping to transistor radios; the bar-room juke; break-dancers popping and locking to the sonic backdrop of a boom box. After the Walkman, music could be silence to all but the listener, cocooned within a personal soundscape, which spooled on analog cassette tape. The effect was shocking even to its creators. “Everyone knows what headphones sound like today,” the late Sony designer Yasuo Kuroki wrote in a Japanese-language memoir, from 1990. “But at the time, you couldn’t even imagine it, and then suddenly Beethoven’s Fifth is hammering between your ears.”

The initial incarnation of the Walkman, the TPS-L2, was envisioned as a toy for Japanese high-school and college students to use as they studied. (Sharp-eyed fans will recognize the distinctive silver and blue TPS-L2 as the model carried by Peter Quill in Marvel’s “Guardians of the Galaxy” films.) Sony’s chairman at the time, the genial Akio Morita, was so unsure of the device’s prospects that he ordered a manufacturing run of only thirty thousand, a drop in the bucket compared to such established lines as Trinitron televisions. Initially, he seemed right to be cautious. The Walkman débuted in Japan to near silence. But word quickly spread among the youth of Tokyo about a strange new device that let you carry a soundtrack out of your bedroom, onto commuter trains, and into city streets. Within a year and a half of the appearance of the Walkman, Sony would produce and sell two million of them.

While the Walkman was far smaller and lighter than any tape deck that had come before, it remained stubbornly large. The technology of the day precluded Sony’s engineers, who were renowned as wizards of miniaturization, from whittling their portable stereo down to anything smaller than the size of a paperback book. Oversized for a pocket, the Walkman obligated the user to carry it by hand or sling it in an included belt holster. Even stranger, by current portable-listening standards, were the Walkman’s headphone ports—plural—and a built-in microphone. The Walkman was initially designed to be used in tandem: a “hot line” button paused the music and activated the mic, letting two users chat even with headphones on. This specification had come at the insistence of Morita, who had irritated his wife by not being able to conduct a conversation while testing early prototypes at home.