In a recent essay for The Slate, Simon Reynolds mused on the practice of artistic theft, in particular the "emerging movement of critics, theorists, writers, and artists [who] argue that techniques of appropriation and quotation are inherent to the creative process." His focus was on art and literature, but he touched on music and sampling too, noting that "remixing and mashups are familiar — indeed, somewhat tired — notions in dance culture". Like most things Reynolds writes, it is well worth a read, but the point I was particularly interested in was one he raises in conclusion:

"The stealing and the storing is the easy part. The much harder — and forever mysterious —stage is the transformation of the borrowed materials. Recreativity has nothing to say about this stage of the process, the bit where, every so often, genius comes into play. It's not the fact or the act of theft but what's done with the stolen thing that counts."

Obviously, when one musician is commissioned (or if that's too grand a term, asked) to remix another, there is no question of any artistic theft going on. The original artist is credited, the remixer compliant with their secondary role – the hierarchy of creativity is not affected. In rare instances, a remix can transcend the original (Armand Van Helden's remix of 'Professional Widow' by Tori Amos, or Skream's rework of La Roux's 'In For The Kill', for example), but more commonly, the remix is just padding. Back in the day remixes were used to fill out the endless formats, and occasionally a remix was part of a concerted effort to break a track or act to a different crowd or, in the worst excesses, to give a stodgy Dad-rock band some dancefloor cred.

All of this pontificating is a rather grandiose way of prefacing a review of Mogwai's latest remix album – A Wrenched Virile Lore. Firstly, can we just all agree that this is a magnificent title? The Scots post-rockers have previous form for this (the concept and the shit-hot title) – their first remix collection, released back in 1998, was called Kicking A Dead Pig. Anyway, digression… Why bother releasing an album of other people's interpretations of your songs? Surely the concept is an anachronism, or even worse, a cash in? People just get on and do remixes these days, they don't wait to be asked. You can find unbidden reworks all over the internet, especially as advances in technology mean that you don't even have to get the parts from the artist, you can strip a song down to the source elements yourself. And as Reynolds says, the remix is a rather tired concept in music. But, his other point is more pertinent to this review – it's all about what you do with what you're given ("the transformation of the borrowed materials") that decides whether a project like this will sink or swim. And Stuart Braithwaite and co have selected a cast of remixers that have sent this baby front crawling through stormy waters like Michael Phelps pumped to the gills with Nandrolene. In short, it is AMAZING.

But then, why should we ever have doubted Mogwai? They're practically superheroes now, having stuck to a formula but somehow made it sound increasingly more vital and thrilling with every album. They don't do anything unless it's solid gold. Their most recent and seventh studio offering, Hardcore Will Never Die, But You Will (the songs of which are the source material for A Wrenched Virile Lore), was to these ears their best – a captivating showcase of their mastery of the quiet/loud dynamic, with intense monolithic riffing embellished by expansive melodies and motorik grooves.

Almost to a man (there's the odd fail, but they're near misses not massive stinkers) the remix team delivers, transforming the borrowed materials into something not better, but of equal merit – the songs deserve to exist in their own right. Justin K. Broadrick of Godflesh has billed his take on 'George Square Thatcher Death Party' as a "reshape". Whatever you call it, it's damn fine; industrial-strength gloomy shoegaze, with woozy synths and a thunderous drum break. The 'EVP Mix' of 'White Noise' by Cylob sounds like an ancient relic from the 1980s synth pop era, made on an Amiga and then buried in a time capsule, to be dug up, spruced up and presented here; the eerie treated vocal line is like something from Kraftwerk's Radio-Activity.

The Not Not Fun-signed LA producer Xander Harris shoves 'How to Be a Werewolf' onto the peak-time dancefloor, grafting a pumping 4/4 beat on to the song's original life-affirming riffs – it's incongruous, sure, but it works. Zombi tackle 'Letters to the Metro' and end up sounding like John Carpenter producing The Human League, with an undulating synth riff that's a ringer that in Depeche Mode's 'Never Let Me Down Again'. In complete contrast, Chemikal Underground's RM Hubbert delivers a cover, not a remix, utilising his prodigious finger-picking guitar skills to turn the previously Neu!-esque 'Mexican Grand Prix' into a hushed, woodsy folk number. San Francisco synth-punkers the Soft Moon reveal themselves as possible heir-apparents – their version of 'San Pedro' is Young Team-era Mogwai backed by the evil analogue krautrock of Add N To (X). Tim Hecker's version of 'Rano Pano' evolves from Boards of Canada-apeing nostalgic melodies to disquieting, hypnotic ambience, while the Goblin-loving horror soundtrack maestro Umberto reimagines 'Too Raging to Cheers' as 'Axel F' on Mogadon.

Klad Hest's (Matt from Beak>) rework of 'Rano Pano' is one of those aforementioned near misses; a rudimentary serving of Braindance that Rephlex were chucking up in the early 00s, all squiggly acid lines and discordant chord sequences, but even here the source melody elevates it above the ordinary. And Robert Hampson of Loop is spoiled with 13-minutes for his shifting, ambient guitar reinterpretation of both 'White Noise' and 'George Square…' entitled 'La Mort Blanche'. It's probably about 6 minutes too long, but then again, this is Robert fucking Hampson of LOOP we're talking about, and if it was half an hour long I wouldn't have sent it back. It's an indulgence sure, but we'll let him off because it's stunning. "The hallmark, or proof, of genius," says Reynolds, "is not merely transmitting or remixing. It's fashioning something that others will someday want to steal." Genius is definitely pushing it, but A Wrenched Virile Lore is stuffed with ideas worth pilfering, not least the realisation that the remix album itself isn't a relic.