“This is how we started out you know,” says Paul McCartney during the 1991 all-acoustic performance captured on Unplugged: The Official Bootleg, referencing the Beatle’s humble skiffle-band beginnings. And the stripped-down live recording indeed offers a peek at his roots, but it made major waves in a larger context, helping to popularize MTV’s whole Unplugged phenomenon.

When McCartney played the still relatively unknown MTV Unplugged program in January 1991, he had just recently gotten off the merry-go-round that was 1989-90’s 103-show the Paul McCartney World Tour, where he played the planet’s largest venues, bringing stadium-sized arrangements to his biggest hits. It’s clear that he relished this opportunity to take an opposite approach to live performance.

There is no overlap whatsoever in the song selections of Unplugged and 1990’s double-length Tripping the Live Fantastic, which documented the huge tour. Instead of an endless onslaught of Beatles and Wings evergreens, the acoustic record features seldom, and even never, recorded McCartney compositions as well as a hearty helping of covers, including some sweet surprises.

Fully half of the tracks on the album are cover tunes, and Unplugged opens up with one of the most historically significant. Besides being one of the building blocks of rock ‘n’ roll, Gene Vincent’s “Be-Bop-A-Lula” was in the repertoire of the Quarrymen, McCartney and John Lennon’s late-‘50s skiffle band, as well as a part of the Beatles’ Hamburg-era songbook. Legend has it that the pre-Macca Quarrymen were playing the song at a gig on July 6, 1957, the day Lennon and McCartney met for the first time. Lennon later recorded a solo version of the song, on his 1975 covers album Rock ‘N’ Roll. Even armed only with acoustic axes, the skiffle-schooled McCartney and his band burn their way through the rockabilly milestone with elan.

In terms of Beatles history, the tune that follows occupies an equally important place. The somewhat Buddy Holly-esque “I Lost My Little Girl” is said to be the first tune McCartney ever penned, at the tender age of 14. But it took the song 35 years to turn up on an album.

We get a little more insight into the particulars of McCartney’s early influences not only from his performance of bluesman Jesse Fuller’s signature song, “San Francisco Bay Blues” (a Quarrymen favorite), but even from the introduction, in which McCartney lets listeners know that the first version of the tune he became familiar with was by folk legend Ramblin’ Jack Elliott. Covers of Bill Monroe’s bluegrass classic “Blue Moon of Kentucky” and the Jimmy Reed hit “Hi Heel Sneakers” similarly highlight the musical world the young McCartney opened his ears to in his earliest years as a musician.

But not all of Unplugged’s cover tunes hail from his formative years. Maybe the most unexpected entry here is a simmering cover of Bill Withers' moody ‘70s R&B gem “Ain’t No Sunshine.” McCartney may have cut his teeth on rock ‘n’ roll, but when he wants to, he can let out a soulful moan that makes you think the Quarrymen came up on Curtis Mayfield covers or something.

A slow-burning version of the bluesy “That Would Be Something,” a deep cut from 1970’s McCartney, notwithstanding, McCartney still finds some time to sprinkle a handful of Beatles tunes into the set list. And in this context, songs like Revolver’s graceful ballad “Here, There and Everywhere,” Rubber Soul’s bluegrass-flecked “I’ve Just Seen a Face” fit right in.

When McCartney made his MTV Unplugged appearance, the show had been around for a couple of years, but hadn’t gained that much attention. One reason might be that it started out featuring mostly artists with significantly less than household names, but the show probably also needed someone like McCartney to do what he did next: release an album of his Unplugged appearance. Up until that time, none of the program’s guests had made that move before.

But when McCartney’s Unplugged album came out, just a few months after the show was shot, the concept suddenly started picking up steam. Pretty soon Unplugged became all the rage, and more and more top-tier artists were turning up to be featured on the program. But few of them would embrace the idea as literally as McCartney; unlike many other Unplugged guests, McCartney and his band didn’t have any of their acoustic instruments going directly through amps or a P.A. system. Instead, they were all carefully close-miked to give the whole affair a feeling of physical space, and air moving through the room. Now that’s unplugged.

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