They were one of the first bands the British press categorized as part of the NWOBHM (New Wave of British Heavy Metal) movement, but by the time Def Leppard released their fourth record, Hysteria, on Aug. 3, 1987, they had completely shattered the mold and discovered a sound based on catchy melodies, heavily processed drums, layered, shimmery walls of guitar and clean, crisp vocals. If 1983’s Pyromania marked Def Leppard’s toe-dip into pop, Hysteria was a cannonball off the deep end. Then again, guitarist Phil Collen says they never liked being categorized with British metal bands.

“Even when we were grouped as part of the New Wave of British Heavy Metal, we didn’t think we were at all like the other bands people were talking about [including Iron Maiden and Diamond Head],” he told me in 1999. “We never wanted to be a metal band, ever. We're about as close to metal as we are to Madonna.”

Despite their disenchantment with metal, Def Leppard still had a slew of commercial metal fans and glam rock fans who didn’t bail on them, and with radio hits like “Pour Some Sugar on Me,” “Love Bites,” “Animal” and “Rocket,” Def Leppard attracted a new fan base from fans of U2 and Prince to kids who had just one or two hard-rock records in their collections.

Def Leppard, "Animal"

“We’ve always wanted to be a band for the people,” Collen says. “When we started working on Hysteria we had just sold eight million records with Pyromania so we knew we had a fanbase. We weren’t necessarily trying to top that because you can’t go into something saying, ‘Okay, yeah, this one’s going to sell more than 8million copies.’ That’s a lot of records. We just wanted to make a record with good songs that we really liked and that were maybe a little more polished and more modern sounding. Even when we finished Hysteria we had no idea how it was going to do, but it felt like a triumph for us.”

Within days of its release, it was clear that others viewed it as a triumph as well. Hysteria reached No. 1 on both U.S. and UK album charts and went on to sell over 12 million copies in the States and over 20 million copies worldwide. And it proved that after a four-year wait for a new album, the public was still eager to embrace Def Leppard’s heavily processed sound.

Hysteria wasn’t an easy record for the band to make, and came to life only after some serious drama and soul-searching. By the time it was released, Def Leppard’s drummer Rick Allen had lost his arm in a near-fatal car crash and the level of stress they were under while writing the songs made the band consider breaking up. Then, after they toured for Hysteria, guitarist Steve Clark died from an overdose.

“People talk about ‘The Curse of Def Leppard,” and that’s so strange to me,” Collen said. “We’ve been a band since 1977. We’ve been like a family, and things happen in any family. People have accidents, people die. You enjoy the good times, and you stick together and help each other through the bad times.”

There were both good and bad times while producer Mutt Lange -- who had been with Def Leppard since their second album, 1981’s High ‘n’ Dry -- worked on Hysteria. From the start, his goal was to help create the most commercial hard rock album of all time, and reaching that goal put everyone in a pressure chamber, from the engineers to the band members. “His blueprint for Hysteria was Thriller,” recalled Collen. “He figured, ‘Well, that album's got six or seven hit singles on it. Let’s make a rock version of that.’ Talk about a challenge. And to be honest, Hysteria was a difficult record to make. Nothing came easily. We worked on it for a long time and it cost lots of money, but eventually we got there.”

To give Hysteria a sound that would stand out from the rock records flooding the marketplace, Lange used a variety of technology. All of the guitars were recorded on a Rockman amplifier and dozens of tracks were recorded and layered for every take. Then the drums were sampled individually and played through a Fairlight digital sampling synthesizer. Finally, the takes were saturated with echoey reverb, giving the songs a stadium rock vibe, even without the low, booming tones of most hard rock.

“That was a hell of an experiment at the time,” Collen said. “It was excruciating to record. We just redid stuff over and over and over -- guitars, vocals, everything. And then if it didn’t sound the way we wanted, we’d modify it and start the whole process over again until we found the parts that worked best for the song. Then we’d move on to the next one.”

Def Leppard, "Love Bites"

There’s no question that Lange played a major role in sculpting the sound for Hysteria. And when Lange bailed on the project in the pre-production stages due to mental exhaustion, it looked like Hysteria might turn into a completely different types of release. Def Leppard hired Meat Loaf’s songwriter Jim Steinman to replace Lange. But Steinman wanted to capture the band with traditional hard rock production techniques, and Def Leppard was unhappy with the sound he was getting. The band members let him go and then tried to produce the album themselves in an effort to capture Lange’s widescreen sound, but soon they shut down shop. The situation went from bad to tragic.

On Dec. 31, 1984, drummer Rick Allen was speeding along a country road in Sheffield, England, with his girlfriend Miriam Barendsen. When he tried to pass another car, Allen lost control of his Corvette C4, which bounded off a brick wall and flipped through a field. Allen’s left arm was severed in the accident and he nearly bled to death before he paramedics got him to the hospital. Doctors were unable to reattach the arm, but Allen was unwilling to give up on playing drums in the band. After he had healed from the accident, he started playing again and used his feet to trigger drum sounds he used to play with his left arm.

“People have asked us why we didn’t find a new drummer after Rick’s accident,” Collen said. “That wasn’t even a thought. We encouraged Rick to get his spirits back and work hard to rejoin the band. I mean, for God sakes, you don’t kick a man when he’s down. How horrible would it have been to say, ‘Okay, you just had this horrible accident, and that’s really traumatic for you. But sorry, you’re out of the band.’ No way. We were determined to keep going with Rick.”

Def Leppard, "Pour Some Sugar on Me"

Right when Def Leppard were ready to continue working on Hysteria with Allen, Lange contacted them and said he was available to get back into the studio if they were interested. Def Leppard worked steadily with Lange from mid-1986 through January, 1987. During their final recording session, they tracked “Armageddon It” and the last-minute addition, “Pour Some Sugar On Me,” which became the most popular song on the album.

“‘Pour Some Sugar on Me' was based on a rap song, which sounds so silly coming from this British rock band,” Collen said. “It had a wacky vocal, and that was pulling from areas that we'd never been close to before but were excited to mess around with.”

Hysteria was the last album guitarist Steve Clark worked on with the band. A problem alcoholic, he went in and out of rehab several times in the six months before he died from an overdose of codeine, alcohol, diazepam and morphine. Clark was replaced by former Dio guitarist Vivian Campbell, who remains with the band to this day.

On Oct. 22, 2013, Def Leppard released the double-album Hysteria: Live at the Joint Las Vegas. Recorded on March 29 and 30, 2013 during the band’s residency at the Las Vegas Hard Rock Hotel and Casino, the first disc features Hysteria in its entirety as well as two hits from Pyromania -- “Rock of Ages” and “Photograph.” The second CD featured more obscure cuts from the band’s catalog, which Def Leppard had performed as the opening act to their own shows, using the name Ded Flatbird. The set included all of side one of the band 1981 album High ‘n’ Dry.

Decades after releasing Hysteria, Def Leppard continue to play many of the songs from the album as staples of their set. On their 2015 summer tour with Styx and Tesla, the band regularly performs “Animal,” “Armageddon It,” Love Bites,” “Rocket,” “Pour Some Sugar on Me,” and “Hysteria.” It seems Mutt Lange had it right all along when he said Hysteria would be the hard rock version of Thriller.

Def Leppard, "Hysteria"

Loudwire contributor Jon Wiederhorn is the author of Raising Hell: Backstage Tales From the Lives of Metal Legends, co-author of Louder Than Hell: The Definitive Oral History of Metal, as well as the co-author of Scott Ian’s autobiography, I’m the Man: The Story of That Guy From Anthrax, and Al Jourgensen’s autobiography, Ministry: The Lost Gospels According to Al Jourgensen and the Agnostic Front book My Riot! Grit, Guts and Glory.