Miles Davis: 'I could definitely hear right away that this was going to be one of the baddest motherf***ers who had ever played a set of drums."

The Tony Williams Lifetime's Emergency! Is a furious, stunning, seminal album. In 1969, it's explosive sound divided critics in both jazz and rock but is now rightly regarded as groundbreaking. A musical statement so bold and irreverent that it was revolutionary, it's one of the most important records you will ever hear. With Emergency!, provocative percussionist Tony Williams unified the most vital sounds of the era and galvanised the creation of jazz fusion. A sprawling double LP that shattered the boundaries between jazz and rock, it forged fresh frontiers by unleashing dense, courageous and fantastically mysterious music.

The group was founded by Tony Williams, a member of Miles Davis' radical 1960s quintet, out of his desire to fuse the influences of modern jazz and rock music. To effectively meld the scorching bop of Coltrane with the raging rock of Hendrix, in the process crafting, as Mojo put it, 'jazz-rock's equivalent of Are You Experienced?'. The album's urgent title was profoundly significant for Williams: "It was an emergency for me to leave Miles and put that band together (... ) and I wanted to play an emerging music that was my own.' The band he formed was one hell of a power trio, comprising nothing but raw virtuosity: Williams's colossal drumming, John McLaughlin's pioneering, aggressive guitar playing and Larry Young's freeform organ work.

The album's sound is incredibly fierce and inordinately intense. Indeed, the group were famed for playing "louder than rock'n'roll", as Herbie Hancock said of going to hear them live in 1969: 'This is something new... It was exciting and very arresting. It snatched you. It yanked you out of your seat." Ian Carr, of Nucleus, was equally impressed: 'The only other comparable band that existed... They were incredibly loud, but we liked what they were doing. Fundamentally they had a different approach from ours, with some very highly arranged things that featured Larry Young's organ blending with the guitar, as well as intricate passages where Tony doubled the melody on the drums.'

Like all the very best records, Emergency! #takes multiple listens for your brain and body to decipher everything going on, to truly process and appreciate the details that our senses are throwing at us. It's a mesmerising, rough sound yet the intuitive interplay of all 3 musicians is super-tight. The tunes are strung out and jamming but retain a tight rhythmic focus.

The incendiary title track immediately presents jazz-rock's chaotic birth. After Williams's ominous snare-roll signals the brewing storm, the snarling band blasts it's way through the gate in truly breathtaking fashion, fuzzed-up wahed-out guitar riffs vying for prominence with gnarled, insistent organ. Thrillingly, Williams manages to both acrobatically crash over every element of his drum kit while keeping the whole groove undeniably funky. 'Beyond Games' is a gloriously volatile freeform, featuring Williams' bugged out vocals, whilst the 12-minute 'Where' is another deep, wild jam. It's disorientating and humid with weird rhythms, abrupt vibe shifts and semi-classical lines running between guitar and organ. It's like nothing else you've ever heard, absolutely vital.

With the buoyant "Vashkar", we begin to experience jazz-rock's many angles; imaginative melodics, taut dynamics and as torrent of searing heat. Perhaps the most economical track on Emergency!, it's the most instant. In a recent retrospective review in Pitchfork, Emergency! #received a monumental 9.0 ranking. The writer Hank Shteamer correctly gushed: 'Driven by a tumbling Williams pulse, the trio dances through the complex stop-start theme, ending each iteration with a dramatic full-band rest. Then, in the middle of McLaughlin's scrambling solo, Williams starts playing an embryonic version of an extreme-metal blastbeat, alternating snare and bass in rapid succession while rising precipitously in volume, as Young joins in with shuddering note clusters. During Young's solo, the organist seems to incite Williams to repeat the move with his increasingly frenzied lines, and soon all three musicians are hurtling toward a supernova climax.' WOW!

The laconic 'Via the Spectrum Road', a brilliant pop-psych tune, was sampled by Showbiz & AG on their classic debut LP. It oscillates between a tranquil funk groove and strutting improv interludes. The pyrotechnic jam 'Spectrum' wakes things up again with pure, molten jazz lava and crazy soloing from all involved. A breathtaking, kaleidoscopic 13-minute cycle through ferocious noise, 'Sangria For Three' is a sublimely frenetic detonation of distilled (acid) jazz rock. To quote Shteamer again, 'Don't let the track's breezy title fool you: As much as, say, "Sister Ray" the year before or "Fun House" the year after, this is punk before punk.' Closer 'Something Spiritual' finishes this jaw-dropping set with a driving, unrelenting heavy guitar and organ freakout, backed high in the mix by Williams's untamed funk before unsettled dissonance rides us out.

Listeners will be struck by the timelessness of Emergency!; dank, trance-inducing voodoo jazz that's intellectually challenging at the same time as viscerally thrilling. The blurred cover photo, whereby the convulsing vibrations of this sonic apocalypse ensure it looks exactly as the record sounds - out of focus - has been delicately restored at Be With HQ. Mastered for vinyl by Simon Francis and cut by Cicely Ralston for Alchemy at AIR Studios, the magnificent grit and spontaneity remains dizzyingly intact. If you're a jazz fusion fan and don't already have this, consider ownership of this record as an Emergency!