After years of eligibility, Def Leppard are finally entering the Rock and Roll Hall of Fame in 2019. While they're best known for the sonic maximalism exhibited on such mega-hit albums as 1983's Pyromania, 1987's Hysteria and 1992's Adrenalize, a look at the creation of Def Leppard's very first EP -- released 40 years ago this month -- reveals a DIY aesthetic as crude as the operations of contemporary U.K. crust-punk luminaries such as Discharge and Crass.

"We got together in my parents, well my bedroom in my parents' house," singer Joe Elliott said during a 2017 interview with the Life In The Stocks podcast. "I met [original guitarist] Pete Willis in the street and just said: 'I just bought this Les Paul copy.' Thirty quid from a junk shop on London Road. And you know I was inspired in '77 by the likes of the Pistols and The Clash who, you know, even I could tell they weren't exactly musicians in the sense of playing guitar like Jimmy Page or Eddie Van Halen or whatever. And I thought well if they can, I can."

Yet in spite of the primitive exterior of The Def Leppard E.P. -- its cover a cheeky take on the band's name in a send-up of the His Master's Voice logo (which Elliott's mum helped assemble) -- the initial lineup (Elliott, bassist Rick Savage, guitarists Willis and the late Steve Clark, plus session drummer Frank Noon) was already gunning for a position far above the underground from the get-go. Post-punk might have been in the periphery of the band's world in Sheffield, England (Pulp and The Human League were gearing up for takeoff around the same time as Def Leppard) but these guys were still very much high on the glam albums of their youth, looking to bring the glitterbomb pop of Marc Bolin and David Bowie into the intense nature of England's new wave of hard rock and heavy metal.

"We grew up on a bunch of British pop music that never even infiltrated the American psyche," Elliott told legendary Dallas rock DJ Redbeard on his In The Studio With Redbeard program. "Of course we dearly love bands like Led Zeppelin and [Deep] Purple, what you may call heavier album track bands, but I think when we first started listening to radio it was the British Top 40 on (BBC) Radio One and Radio Luxembourg, which was a little more adventurous with their playlist. We were fortunate that the British music scene from '70- '71 to '74 had a lot of the bands like Slade and Sweet and David Bowie and T. Rex were very guitar-based three-minute pop songs, which by today's standards may be called hard rock, because it was just big drums and guitars and big honkin' choruses. Some of them cheesy, some not. But you have to weed through the dross. A lot of the Slade singles were top notch."

Only 1,000 copies of the EP were initially pressed up on the group's own Bludgeon-Riffola imprint. Thanks to an early push by John Peel on his legendary BBC Radio 1 show, the EP enjoyed a modicum of success that yielded a couple of repressings, a spot on the lower end on the BBC singles chart and a record deal with Mercury Records. The band -- joined by teenage drummer Rick Allen -- went on to cut their debut LP On Through the Night, which Rolling Stone critic David Fricke would praise in the June 26, 1980 issue: "They not only respect their elders, they've taken cues from their New Wave peers, too. Ignoring heavy-metal's unwritten law requiring long guitar solos in every other tune, guitarists Pete Willis and Steve Clark shoot from the hip, packing their licks into tight, three-minute pop arrangements."

Two songs from the EP were reconfigured for Night: “Getcha Rocks Off” (now simply called “Rocks Off”) and the proggy seven-minute epic “The Overture.” Meanwhile, “Ride Into the Sun” would be given a complete overhaul with the help of current guitarist Phil Collen (who had performed in the underrated British glam group Girl when the Leppard first came together) for use as the B-side to Hysteria’s hit title cut. Additionally, the original three-song EP itself was reissued in 2017 as a Record Store Day exclusive.

Yet The Def Leppard E.P. is far more than a minor curio on the path to the group's journey to the Rock and Roll Hall of Fame, an immortalization they so richly deserve for bringing glam to the slam of British hard rock and metal. Those three initial songs serve as the blueprints for a style of hard rock that remains essential to this very day, despite the varying degrees of Mutt Lange-laced overdrive enhancing it along the way. Elliott has not forgotten its importance after 40 years.

"We were so young and I think that we had that youth on our side which really helped," Elliott said in a 2016 radio interview. "And you know especially my parents weren't gonna put a blocker on it. They said no, if you give it a go pay me back but here you are. And that EP got picked up by the likes of Mr. John Peel. The legendary DJ, in England anyway. He played it. That got heard by the A&R men at record companies who always listened to John Peel. And it started creating an interest and it was just the acorn. It was literally the seed and then people started coming to attend the shows and A&R men started coming and there was this like battle of, you know, ten labels to sign the band. And it was all down to that EP."