It's late on a Monday night: September 9, 1996 - might even be the early hours of Tuesday by now. In a tiny basement club, the Flavour of the Month hip hop night, run by the Choice FM rap show DJ, 279, is in full swing. It's become the hub of London's small but vibrant hip hop scene almost in spite of itself: the venue doesn't list the club in its press ads or on flyers, so the only people who know about it are listeners to 279's show, and the hundred or so regulars who turn up, month-in, month-out, for the tried-and-tested blend of live performance, open-mic freestyles, and DJ-spun anthems from hip hop's present and recent past.

There's sometimes an edge to the atmosphere at Flavour, but usually that's just down to the combative verbal sparring that makes the open-mic sessions such a draw. Tonight, though, is different. Hip hop is in crisis: the music blamed for all manner of societal ills by an ill-informed media looking for something to explain events on the other side of the globe. At this moment, in a Las Vegas hospital, Tupac Shakur is in a coma: details in this largely pre-internet world are still sketchy, but everyone here knows he was shot multiple times while riding in the passenger seat of his label boss's car on Saturday - no-one yet knows that, possibly right at this moment, he's having a lung surgically removed. Given his string of run-ins with the law and previous history of surviving life-threatening ordeals, many probably assume he'll pull through.

But this is the Flavour crowd - hip hop purists, devotees of the art form, not thrill-seekers drawn to the music by the soap operas its stars are starting to insist on living out, or the voyeurism implied in violent rhymes about violent times. These people are all about lyricism and craft: about music, poetry and microphone skills. And, contrary to what will become the accepted wisdom in the years that lie ahead, they don't consider Shakur to be one of the greatest rappers who ever lived: in fact, at this moment, quite a few of them are pretty angry with him. They see him, perhaps, not as the victim of an orchestrated campaign by American law-enforcement to silence a voice of potential insurrection, but as someone who has, either by unintended lassitude or deliberate calculation, blurred the boundaries between life and art. Not content with rapping about crime stories and gang violence, Tupac has become one of those characters he and others spend their studio time sketching out in rhyme. And in the process, he's brought the heat on hip hop, got outsiders focusing on it as never before, and none of the attention is going to be good news for a genre that's always faced a fight for legitimacy in the eyes of a wider public. Far from a saint, Tupac is, right now, to these people, the epitome of the hip hop sinner: an enemy of the art form.

But still, there are cooler heads and calmer thoughts among the Flavour crowd. The guy's been shot, for pity's sakes: he's fighting for his life, and whatever else he may or may not have done, or thought, or said, or implied, or come willingly or otherwise to stand for, he's a human being and a part of this culture, and this is undoubtedly his hour of need. Respects need to be paid, and even this most secular of musics can surely offer up its own brand of prayer. So the call goes out to the DJ booth - play a song for 'Pac.

It's that part of the evening where 279 heads upstairs to settle the night's accounts with the venue, so the Technics are manned by his affable sidekick, Big Ted. A skilled mix DJ, Ted will eventually get his own radio show, he and partner Shortee Blitz making a virtue of their larger-than-life physiques by branding themselves The Chubby Kidz. Tonight, though, he will write his place into the history of hip hop as passed down by the few here to witness it.

In response to the growing clamour, Ted cues up a 2Pac record. He chooses an early single, the sex-themed party track 'I Get Around'. Maybe it's a poor choice - the side of Pac destined to get this particular crowd's hackles up even more than might have happened with 'California Love' (given that the main sample in that track was used a decade earlier by the Ultramagnetic MCs, the Flavour aficionados doubtless would consider it 'biting', and thus beyond the pale) - or maybe the reaction would have been the same whatever record 2Pac track Ted had played. But as soon as the crowd recognises the song - within a couple of bars of its squeaky synth intro - the sound is all but drowned out by a sustained bellowing of boos.

Some people start to get visibly angry. There are fists being shaken, people gesturing dismissively at the DJ booth, turning their back on Ted and the decks and the music he's playing, as if disgusted. The noise increases as the first verse gets going, the cocksure, happy-go-lucky sentiments and Pac's multi-tracked voice the antithesis of what, to this crowd, constitutes real hip hop.

And suddenly there's another noise, louder: the sound of the needle being dragged slowly and deliberately across the record. Every head in the room turns to the booth as Ted rips the vinyl off the platter and - I swear I remember seeing this, but at 16 years' distance I can't be sure I haven't invented this one detail - throwing the record onto the floor. There's silence for a heartbeat, then he hits "start" on the other deck, and out of the speakers booms an iconic, unmistakable bass line. Sample-hunters, some years later, will discover that it originally came from the intro to the second track on an obscure 1968 album by Cannonball Adderly's younger brother, Nat - but right now, the only thing that matters is that Ted is playing 'Know The Ledge' - the theme to Juice.

It's a moment of genius: hip hop history coming to handle the crises of the present, a vinyl air-strike called in by a master tactician of the wheels of steel. In the film, Shakur had played Bishop, a teenage hoodlum whose instabilities cause him to spiral down into a hell of his own making. The parallels with the rapper's current predicament don't need to be underlined: and the contrast between the clumsy, banal, almost artless 'I Get Around' and the dazzling poetry and rough-hewn beats tumbling out of the speakers couldn't be more indelibly drawn. The boos are replaced by cheers. And the most utterly appropriate tribute to the ailing, soon-to-die 2Pac is delivered, in a fashion that only an art form as complex, contentious and combative as hip hop is capable of. Crucially, cruelly, even comically, there's another more subtle point that folks here will, later on, come to realise: the guy who would go on, in death, to become arguably rap's most potent icon is actually best honoured by a record he didn't even make.

Anyone still reading might be forgiven for wondering how a piece about Eric B & Rakim's fourth LP, released in 1992, can avoid mentioning either man by name until a third of the way through. But there is no better illustration of the power of the music they - or, more accurately, in this case, Rakim - made than that unforgettable moment.

Conventional histories teach that the first Eric & Ra album, Paid in Full, is the best, with the others largely ignored - but it's actually possible to scientifically prove this not to be the case. Of Paid...'s ten tracks, three are instrumentals, two of the remaining seven were the A and B sides of the duo's first single, and three of the other five were also released on 45s. As great as 'I Know You Got Soul' and 'Eric B Is President' clearly are, a few singles and a couple of instrumental place-fillers do not a classic album make. The eventual follow-up, Follow the Leader, is clearly a better, more cohesive and complete, body of work, and the third - 1990's dense, contemplative Let the Rhythm Hit 'Em, the product of a dark time when Rakim lost his father and the duo had to deal with the death of musical collaborator Paul C, who they'd only just started working with but who had become incredibly important to their process - is shorter but more consistent. It could be their best, but there's also a case to be made for Don't Sweat the Technique - the 1992 swan-song, and a record where Rakim's maturity as a wordsmith and lyrical conceptualist was matched by pugnacious beats he built, often, by himself. In a sense, it's his first solo album in all but name; and it delivers at least eight, maybe nine, of the finest, most fully resolved, pieces of hip hop music ever created.

The back-story to the album was typically convoluted, even by the peculiar standards Eric and Ra had ended up embodying. Their complex relationship was very different to that supposed by fans. As Rakim told it in 1995, the partnership was never one of creative equals: the notion that Eric, as the DJ, made the beats while Rakim handled the rhymes wasn't anything like how they worked it in reality. As far back as 'Eric B Is President', Rakim had been choosing the samples and loops he wanted to rap over, keen to keep to the harder-edged sounds he'd grown up freestyling to in the park jams where he learned his craft, and often drawing the original records from his parents' collection. Eric contributed ideas - many of them inspired - and did the frequently superlative scratching; the instrumentals were his work, and he was the live DJ.

There were mutterings and disagreements, but nothing too problematic: Rakim's view was that Eric had discovered the then 15-year-old emcee and given him his chance - the DJ had headed out to isolated Wyandanch, Long Island, looking for a rapper to team up with, for a shot at recording with Marley Marl that he'd arranged through his brother and the radio DJ Mr Magic. As far as Ra was concerned, Eric could have half the money, half the billing, share the limelight, whatever he wanted - he'd put Ra on. Without Eric B, Rakim was just another kid battling in a suburban park. He'd have given up rapping and knuckled down harder in High School - maybe concentrated on football (he had ambitions to be the NFL's first black quarterback - that wasn't just a rapper boast he put in to 'Keep 'Em Eager to Listen': he - as the cliche goes - had game). But the pair weren't really a functional creative unit built on equal artistic contributions - and as they went in to what would be their final album as a nominal duo, the pair were "kinda havin' a quiet riot," the emcee told me. "We wasn't fuedin', but we had understood that we had differences so we kept our distance and didn't say much to each other, because we knew we were goin' down different roads."

The production - not credited fully on the sleeve - was led by Rakim but involved three other people. Large Professor supplied the tracks for 'Relax with Pep' and 'What's Goin' On?': the Main Source member had been introduced to Rakim by Paul C, and felt he owed it to his late mentor to see through the job he'd begun with Ra. Two further tracks - 'Rest Assured' and 'Pass the Hand Grenade' - were produced by Rich Simmons; Rakim collaborated with a producer by the name of Rashan for 'Teach the Children' and the title track; of the remaining six, five were produced solely by Rakim, who even played drums on 'Know the Ledge'. Eric's contributions to the album were limited to the opening track, 'What's On Your Mind' - a syrupy piece of lover's rap that is an uncomfortable standout in the duo's discography for all the wrong reasons. Initially a demo, it wound up on the soundtrack to the comedy House Party 2, and was added to the rest of an album it bears no formal, conceptual or sonic relationship to, at the behest of the label, MCA, who felt it would be a useful marketing device. It's an ill-starred opening for a record that was completed despite a plethora of problems.

"That album for me wasn't organised right," Ra explained in our 1995 interview. "I found myself in a room tryin' to write 'Relax with Pep' and 'What's Goin' On?' at once. I had the two beats on tape: 'Relax with Pep' was first so I'd write to that, then the other beat would come on and I'd write for 'What's Goin' On?'. Then I'd rewind the tape to the beginnin' and start over again. We didn't get the producers together, shit started takin' so long, and finally MCA said, 'Right, we need it by this date', so it got rushed. An' I had to write two fuckin' records at one time. I don't like to get down like that."

Yet there are few better insights into how great an artist he is than to examine the work he put in on those two tracks, in such far-from-ideal circumstances. Over Large Professor's superbly atmospheric loop from the coda of Rare Earth's sparse, spare, desperately dark psychedelic take on the Temptations' hit '(I Know) I'm Losin' You', Ra's rhymes on 'What's Goin' On?' show him at his zenith as a social commentator. Never really considered a "spokesman for a generation" in the way his two most revered peers - Chuck D and KRS-ONE - routinely were, Rakim didn't just pay lip service to politics or "reality rhymes", and 'What's Goin' On?' manages to seethe and plead at the same time: no mean feat in a genre whose critics maintain it doesn't do nuance or subtlety. And 'Relax With Pep' is that rarest of beasts - a low-key masterpiece, the kind of sublime display of the rapper's art that only the very best could conceive of, but understated to such a degree that few listeners ever really seem to have picked up on how great a piece of writing it is. It's as if Rakim, out of the banal necessities of completing an album to a far-too-pressing deadline, had to craft some restrictive rules for himself if he was to get the work done in time, and in so doing produced a lyric that may be among the most conceptually thorough in even his remarkable oeuvre.

He takes the title's contradiction - how can you be relaxed if you're pepped up? - and works a similar contrast into almost every line of the first verse ("I'm calm but deadly, heat up but cool/ I'm rough as a right hook but still look smooth/ Even when I'm unseen I show and prove"). The second verse is another peach, and gave MF Doom and Ghostface the title for their long-mooted but still-unreleased team-up LP (Swift and Changeable). But the third may be the best of all, and could even be one of the greatest verses even as great a rapper as Rakim has ever written and delivered: it may not mean a whole lot, other than to demonstrate that greatness, but it's so assured and rich, and is carried off with such panache, it's hard not to get intoxicated by it. "Check the Richter Scale, rhymes overload/ Blow up and explode abrupt and reload the code/ You can't pinpoint or locate the rate/ Or evaluate the up-to-date state/ Up-front, laid back, comin' off on track/ Girls want some of this, because I'm all that."

On the four Eric and Ra albums, the tracks usually fit into three categories (four if you count the instrumentals, none of which appear here): there are the Big Songs, the ones that make the weighty statements or which speak to something beyond the moment ('My Melody', 'Follow the Leader', 'In the Ghetto', 'Casualties of War'); there are the Battle Raps and Brags, where Ra smokes the competition without mercy, occasionally naming names but usually not having to ('I Ain't No Joke', 'Lyrics of Fury', 'No Omega', 'The Punisher'), and then there's the rest. The true measure of Don't Sweat the Technique is surely that its other songs are largely as good as the ones in the two main categories. Tracks that might, next to the more consciously "important" ones, at first appear slight ('Pass the Hand Grenade', a brag that would be a standout on an album that didn't contain something as blistering as 'The Punisher', or 'Rest Assured', a track which remains on simmer without ever needing to be brought to the boil) are frequently stunning. Only 'What's On Your Mind?', the 'Mahogany' follow-up 'Keep the Beat' and 'Kick Along' feel less than substantial, and in the latter case, its place right at the end of the album doesn't help: after what's gone before you're expecting the record to end with an emphatic flourish, and the up-tempo, somewhat ordinary, never-quite-sure-what-it's-for yet still pretty good song, which would likely have been strong enough anywhere else, feels somewhat exposed.

'The Punisher' is the kind of record few rappers could dream of. Lesser talents resort to fiction - Rakim battles in metaphor. The posturing of the gangsta is rendered redundant in this 4'10" of sustained and graphic lyrical violence. "I took a kid, and cut off his eyelids," he raps, "killin' him slow, so he can see what I did/ And if he don't understand what I said/ I'm pushin' his eyeballs way to the back of his head/ So he can see what he's gettin' into/ A part of the mind that he's never been to." It's like a nightmarish echo of the imagery he used on the dazzling Follow the Leader four years earlier, where he guides his listener into outer space, then reaches into their head to change their mindset: "world's out of sight/far as the eye can see, not even a satellite/Just then you turn around and look/And as you stare into darkness, your knowledge is took." When he's in this kind of mood, in this sort of form, nobody - nobody - can touch him.

So the kind of material that one might consider "filler" is a cut above - but that wouldn't mean much if the Big Songs weren't up to par. And on ...Technique, the Big Songs are humungous. As well as the magisterial 'Know the Ledge' - written in two hours spread over two days in the studio, after Ra had attended a screening of the then still unfinished Juice, yet still a piece of tremendous focus and erudition, filled with thought-images as complex and resonant as "In control of many, like Ayatollah Khomeni/ Hang out with Smith and Wesson, don't try to play me/ I'm in war a lot, like Anwar Sadat" in addition to its title's wordplay - there's 'Teach The Children', a track of deliberate and provocative ambiguity that's the record's real opener. And above them all, there's 'Casualties Of War', the product of time spent "shut in a room with just a red light on," "vibin' off" a pugilistic Johnny Hammond sample that Rakim said always sounded to him like war ("I try to see the beat, to visualise the beat, 'cos music speaks," he told me. "Back in the days when I came up I listened to a lot o' jazz which had no words to it - but I used to sit there when I was young and figure that shit out. You get different feelings from different kinds o' shit. So I learned how to listen to a record that I'm about to write to, and picture it, and make it put me in the mood").

Had it been a Tupac song, 'Casualties of War' might have been trotted out by those who want to believe he had the gift of prophecy - in it, Rakim predicts a suicide bomb terror attack on Manhattan, and sure enough, a year after the song was released, the first attempt to destroy the World Trade Centre took place. "The shit happened!" he said, in '95. "I wrote, 'Kamikazes strap the bombs/ No peace in the east, they want revenge for Saddam.' They came over here and blew up the muthafuckin' World Trade Centre. I was gassed when that shit was goin' on, 'cos I could honestly sit here - a rapper - and say, 'I told you so'." What he made of the events of September 2001, in this context, history does not yet record.

Written during the first Gulf War, Rakim's narrative recasts the rapper as an American GI who goes to Iraq, finds himself fighting for a cause he doesn't understand, begins to feel that, as a Muslim, he's fighting for the wrong side, so turns his gun on his commanding officer before covering it up and heading back home. But in New York he's haunted by post-traumatic stress, is incapable of dealing with normal everyday city life, and shoots up a supermarket. Only, the song doesn't actually tell you all the detail - you automatically fill it in for yourself. It's incredible writing - strong lines, boldly drawn, but with an absolute economy of detail. "I always drop science, I always drop jewels, but usually I don't point at nothin'," he explained. "If I'm talkin' about a bottle of water I don't point at the bottle of water. But with 'Casualties Of War' you knew what I was speakin' about."

Yet it's the title track - not quite the album's best - that may most thoroughly sum up what we're dealing with on this record. It's a superlative song, somewhat disfigured in the memory by a video riddled with the kinds of cliche the album, and Rakim's career as a whole, stands in imaginative opposition to. In between nuggets of autobiography Ra explains, for anyone prepared to listen, something of his artistic philosophy, and sketches himself in the colours of myth. It's a rap about rapping, about the permanence of class and the ephemeral nature of style, and embodies the kind of lyricism that lesser talents would kill for. He performs a kind of mental alchemy, turning his rhymes into future fossils and imagining their excavation and interpretation ("They wanna know how many rhymes have I ripped and wrecked/But research has never found all the pieces yet/Scientists try to solve the context/Philosophers are wonderin' what's next"). It's also a bravura performance, giving the lie to anyone who might wish to argue that Ra only flows smoothly; his syllables bounce between the rubber-band bassline and syncopated rim-shots, the internal rhymes inside the lines aiding both the rhythm of the words and the nimble delivery. He was - and remains - the music's undisputed master; the standard by which all others will be judged, and found wanting. And Don't Sweat the Technique, for all the compromises that surrounded its creation and despite its imperfections, may well be his finest hour.