Recalling the price tag for recording Def Leppard's 1987 album, Hysteria, guitarist Phil Collen is still amazed. "Four and a half million dollars!" he says, laughing slightly. "Which was ludicrous. Who knows what that would be in today’s dollars? We had to sell three million copies just to break even, and for a while, we didn't know if we would."

The band had scored an across-the-board smash with 1983's Pyromania, but as they prepared for the follow-up, tragedy struck when drummer Rick Allen lost his left arm in a 1984 New Year's Eve car accident.

"That was a huge blow to us all personally, of course," says Collen. "But Rick came through it all so well, it's unbelievable. The fact that the record took so long to make took a lot of pressure off of him, in some ways. He had the time to learn how to play in a new way, of course, but just the way that he became a new person and learned how to do all the normal things that we take for granted – tying his shoes, cutting a loaf of bread and stuff like that – it was amazing. So Rick was able to get so many elements of his life back before we finished the album and went back into the world.”

Compounding matters was the fact that the group (which at the time also included singer Joe Elliot, bassist Rick Savage and guitarist Steve Clarke) were starting the album without their trusted producer, Robert John "Mutt" Lange, who was committed to working with The Cars on the album Heartbeat City. The band began sessions with noted Meat Loaf writer and producer Jim Steinman.

"It seemed like a good idea at first," says Collen, "but it just didn’t work out at all. So we waited for Mutt. I remember he said to us once, ‘You can be a cool band, a good band or a great band. If you want to be a great band, you have to work harder than anybody else.’ That was it right there. That explains why we went that extra mile, and it was all because of Mutt.”

Already famous – or infamous – for his meticulous nature, Lange took the unusual step of instructing Collen and Clarke - heretofore Marshall amp lovers - to play through Rockman units to achieve a uniform, pristine guitar sound.

“We wanted clarity – clarity with a lot of bottom," says Collen. "Steve and I were working on these elaborate, very intricate guitar orchestrations, and if you’re layering 15 or 16 guitar tracks on a song, Marshalls just aren’t going to work. Using the Rockmans worked very well in that we could fit part upon part upon part, even separate strings. We might have sacrificed some of the hard rock balls element you’d get with a Marshall or something, but the melody and hooks and tone to each part really came through with the Rockmans. It wasn’t all Rockmans, though – there were some parts where we used small Gallien-Krueger amps.”

Going into Hysteria, Lange stated that he wanted the band to make a hard rock version of Michael Jackson's Thriller. Collen states that everybody was on board with such an approach. "Sure, let’s make every song as great as possible – why not?" he says. "Let’s be daring. So many rock bands just follow the stereotype, but Mutt wanted to open us up to any kind of sound, make us like a hybrid in a way, and we thought that was really exciting. He’s amazing at that.

“A lot of rock albums can sound thin and reedy. But listen to hip-hop albums and R&B records – they sound huge! We found that we could get a lot of crossover appeal by making the songs big and open. High ‘N’ Dry had a bit of an AC/DC thing to it. I remember putting my vocals on Pyromania and thinking, This doesn’t sound like anyone else. In fact, it sounded like Def Leppard for the first time."

Hysteria marked the last recordings of Steve Clarke (although he did contribute to the writing of 1992's Adrenalize). The guitarist, who died in 1991, was plagued by alcoholism, but Collen remembers that "he was OK during the Hysteria sessions. It wasn’t until after the Hysteria tour that things came to a head with the drinking. And it wasn’t like he was out of control then, it was the physical reactions he was having. But during the recording of Hysteria, he was OK.”

Collen admits that the three-year process for recording Hysteria did "make us a bit crazy at times, mainly in the beginning," but he clearly recalls the moment when he heard the completed work from start to finish: "We were staying at this little house on a lake in Holland. Steve got a copy and put it on. It was the first time I heard drums on a lot of the tracks, because when I was recording it, a lot of times I played to a click. So I listened to the record and I thought, If it sells one copy and my mom’s the only one that buys it, I’ll be happy. It was the best thing I’d ever heard. I was completely satisfied. I was so proud and pleased. I can still listen to it and feel the same way."

Released on 3 August 1987, Hysteria got off to a slow start (Collen credits strippers in Florida who embraced Pour Some Sugar On Me for kicking the album into the mainstream), but it eventually exploded, spawning seven singles and selling over 20 million copies. "It's been 25 years now," says Collen. "That's enough to make you feel old. Oddly enough, I can remember making the record very clearly. I can remember being in the studio, what guitars we used – I think I remember what we ordered for lunch on some days."

On the following pages, Phil Collen celebrates the 25th anniversary of Hysteria by walking us through the recording of the album track-by-track.