When Leftfield released their debut album in 1995, it changed dance music forever.
Wilfully eclectic, Leftism never settled on a single genre, dabbling in tribal, trance, dub, house and ambient music.
The quality never dipped, proving that a long-form dance record - one that worked as a coherent suite of music rather than a collection of 12-inch singles - was possible.
It was among the first British albums to bring the club into the living room, alongside releases by The Chemical Brothers, Underworld and The Prodigy.
The duo behind Leftfield, Neil Barnes and Paul Daley, had started out in punk bands, and retained the ethos that "music that takes from other places but moves on".
To that end, they borrowed from Afrobeat, indie and punk itself - even cajoling former Sex Pistol John Lydon into singing the album's breakout single Open Up.
These days Barnes continues to record and perform as Leftfield (with Daley's blessing) and, starting on Thursday, he embarks on a UK tour will in which Leftism will be played in full for the first time.
The project was initially planned for the record's 20th anniversary, but is only coming to fruition now, in its 22nd year.
Ahead of the tour dates, Barnes and Daley chatted to the BBC about the making of Leftism, its impact, and their ear-splitting live shows.
What do you remember about the making of Leftism?
Paul Daley: Lots of late nights on the computer, synths and samplers in the week and then I was off DJing at the weekends. It was all very fast moving and constantly evolving, much like the scene at the time.
Neil Barnes: A lot of stuff was done on the fly. We were just being creative in the studio. We weren't completely into indie, we weren't completely into techno. We'd get bored and think, 'We've done a [dance] track, now let's do something down-tempo, or a hip-hop track.'
Is that why it still sounds fresh today?
NB: I think the thing about the album is that it takes you on a journey through electronic music. There isn't one style. It's unusual in that, I think.
PD: I wanted the album to sound exotic, have its own identity and have its own place amongst everything else around at the time. That time was great for music in the UK and as time goes by the '90s, and what happened creatively, is only now coming into focus and I'm really chuffed what we did is considered as something special.
Leftism is frequently cited as a breakthrough, in that it showed dance music could work in an album format. Was that your intention?
PD: It had to be more than a collection of instrumental formula dance records but I didn't really know it worked until I was editing it together at the end. It was a calculated risk at the time but not really intentional. Happy accidents, and all that.
What's the most unusual instrument on the album?
NB: There's a berimbau at the start of Afro Left. It's probably the oldest instrument, aside from hitting a drum, in the world. It's a stringed instrument from Brazil, and they hit it with a pebble. I'll be bringing it on the tour with me.
John Lydon has called Open Up one of his favourite lyrics. Did you realise it was special at the time?
NB: I think it's one of the best songs he ever wrote. When he came in and did the vocal, we realised we had to get the rest of the backing track up to the standard of the lyric. His vocal performance was so incredible, we felt we needed to match it. We changed the bassline radically and added a lot more drums.
Your live shows got a reputation for being louder than Concorde. How bad was it?
NB: The speakers were so loud your eyeballs would vibrate.
Did you really make plaster fall off the roof of Brixton Academy?
NB: A whole bit of the ceiling came down, not just a few chunks. You could see it all over the dancefloor. I've seen worse, though. We once shook a metal grating off when we played a soundcheck in a university. It came down and hit the floor. If anyone had been near it, they'd have been dead. I was terrified.
And we brought a whole bar down in Amsterdam. When our sound man fired up the system, it all came down. Bottles, glasses, everything, flying off the wall. Who paid for it? I have no idea.
What made you decide to revisit the album now?
NB: It just seems like a good time to say "bon voyage" to Leftism. I'm not really going to be playing these songs much more.
How hard has it been to recreate the record for the tour?
NB: It's an unbelievable job of forensic investigation. It's taken months. The album didn't go onto tape at the time, so we've gone back to the raw files to find stuff and build the sounds up so it sounds like the album.
Is the concert a faithful rendition of the album?
NB: It is, but all the tracks are expanded. Some of them are 12 minutes long now. Like Release The Pressure, I've incorporated the single [mix] into the album version, so you get a bit of Cheshire Cat's vocals. And there's no encore. 20th Century Poem was always going to be the closer.
Paul, do you miss playing live? Will you go to see the shows?
PD: I don't really miss anything as I find "missing" things can be negative. I have great memories and still get a buzz from DJing which, in my eyes, is and always has been a performance and artform.
People come up to me and shake my hand for what I did in Leftfield between 1989 and 2002 and that's enough for me.
Finally, what do you see as Leftism's legacy? Who are your direct descendants?
PD: Anyone who's thought, "I'm going to buy some decks, synths, samplers and make a record" since 1989.
Also anyone who has thought, "I can make a record in my bedroom today and play it in my DJ set at the weekend". That was the revolution that has had a massive impact on musical history and which we were part of and it just seems to roll on and get handed down to the next generation for them to put their own stamp on it.
By no means are Leftfield wholly responsible - but we were part of a forward-thinking global musical movement that exploded at the end of the 20th Century and turned pop culture on it's head.
Leftism 22 is out now on Sony. Leftfield tour the album around the UK for the rest of the month, starting in Bristol on Thursday 11, May.