The reappearance of long-lost American rock'n'roll heroes is becoming something of a regular phenomenon. In the past couple of years, we've had Brian Wilson re-emerge from years of self-imposed exile, and even Arthur Lee - long written off as beyond help - has triumphantly revisited the Love canon.
But Bob Weir is different. For a start, he's never been away. As a founding member of the Grateful Dead, that quintessential Sixties band, he was a key component of a 30-year trip into the outer galaxies of collective improvisation. The death, in August 1995, of the lead guitarist Jerry Garcia brought that amazing journey to what seemed a natural end. But such was the power of what they had created that the remaining musicians, in one way or another, kept the creative spirit of the Dead alive in side-projects. It prompted their decision, last autumn, to reform under the abbreviated moniker The Dead - a recognition that, without the presence of the affable genius of Garcia, they could never be quite the same band. As their sell-out summer US tour this year shows, the band have lost none of their huge pulling-power.
For Weir, a key to keeping the light aflame has been his offshoot band, Ratdog, who, following a low-key but ecstatically received European tour last year, return to Britain for a five-date visit, kicking off with a gig at the London Astoria tonight. For fans this side of the Atlantic, it affords an opportunity denied to their vastly more numerous cohorts in the US: the chance to see, in a series of intimate venues, a man who is arguably rock's greatest, if most eccentric, rhythm guitarist.
Weir has come a long way since his early days in the Dead, when, as the 16-year-old kid with long hair and androgynous teenage good looks, he was the most mischievous member of that band of merry pranksters. Now a bearded 55-year-old, he possesses a unique style forged out of the need to establish a personal voice between the extremes of Garcia's wildly inventive guitar-lines and the equally probing playing of Phil Lesh, a bassist who, in effect, uses his instrument as a lead all of its own. First taught by Jorma Kaukonen, Jefferson Airplane's guitarist, and then apprenticed to Garcia as they played in the various groups that preceded the establishment of the Grateful Dead in 1965, Weir has a unique style full of odd time signatures and progressions that no other player outside of hard bop could contemplate. Long derided by some Deadheads for his "pop" sensibilities, he has, ironically, given the Dead some of their most cherished jamming vehicles, such as "Playing in the Band", "Weather Report Suite" and "Estimated Prophet".
The Ratdog that visits Britain this month is a subtly different beast. For one thing, Rob Wasserman, a masterful acoustic bassist, has left to pursue his own projects. His replacement is the English-born Robin Sylvester, an injection of new blood that clearly excites Weir. "Robin is the right player for this band, and he's fitting in just perfectly," Weir says in his laid-back, northern-Californian drawl. "Rob Wasserman used to be my whole band when we started out as a duo in the early Nineties, and he fulfilled that role admirably. But he does a lot of stuff that doesn't work as well in the format of a rock'n'roll band."
Then there is the new trick Weir has up his sleeve. He has been testing out the musical possibilities of looping, digital technology that allows him to build up multiple layers of his own voice, on top of which he can improvise scat vocals.
"Basically, it's a new instrument," he says. "And it's turning out to be a lot of fun. We're working up all kinds of stuff - Ratdog songs, old Dead tunes and new approaches to material, particularly seeing how we can use this technology to arrive at fresh structures. But, basically, we do what we've always done - just go out there and play."
And play Ratdog certainly can. On last year's European tour, even hardened Deadheads were surprised at how good the band were: tight, confident and sharp as a pin, they could move seamlessly from Dylan tunes to old country blues to extended jazzy explorations that reached far into "the zone", a magical place where all six musicians are indispensable components of an awesome improvisatory unit. That tour, for example, included Dead staples such as "Playing in the Band", "Terrapin Station" and acid rock's Holy Grail, "Dark Star", as well as covers, such as a jam taking in The Beatles' "Tomorrow Never Knows" and "Mathilda Mother" by the Syd-era Pink Floyd, the perfect Haight-Ashbury nod to psychedelic Swinging-Sixties London.
If that modus operandi sounds familiar, it is, after all, what you'd expect from a founding member of the Grateful Dead. So how do Ratdog fit into the grander scheme of things? "This band is essential to The Dead; we're The Dead's test monkeys," Weir asserts. "The musicians in Ratdog are all younger [mostly in their thirties], and in some ways they're more game than the guys in The Dead, so they can bring fresh ideas to the repertoire. Their experiences are way different - they're certainly new to my ears, at least."
Just as in the Dead, Weir provides the loosest of structures, so that the music can grow organically and offer constant surprises - to musicians and audiences alike. "What I like to do is perform two, three, four songs in a row in the same metre. That way, the music induces a trance and can get deeper and deeper. We are producing a suite of songs, all interlinked, a continuous stream of music in which we can explore ideas, let them take us into new areas and see what happens."
It's all part of an ethos that, despite what cynics might say, kept the Grateful Dead a fresh and continually evolving organism throughout their 30-year career. It's a world in which songs are important not just in themselves but - in a tradition that's closer to Miles Davis or John Coltrane than anything else in rock - as stepping-off points, allowing the musicians to delve deep into their personal mines of experience to produce multifaceted improvisations of astonishing, telepathic beauty, where ideas can magically intertwine, fresh themes bloom and ripe shoots of melody sprout from deep, dark chasms of chaos.
Much of the Grateful Dead's special chemistry was down to Garcia's sorely missed fusion of blues and bluegrass, Chuck Berry and Ornette Coleman. For many, that the remaining bandmates could carry on after their de facto leader's death was anathema. Weir and his fellow Dead stalwart Phil Lesh took time out to explore different ways of keeping that good ol' Grateful Dead magic alive. In the most enduring of those endeavours, The Other Ones, Weir and Lesh were joined by the Dead's two drummers, Bill Kreutzman and Mickey Hart, and Jimmy Herring, a guitarist of striking ability who, as Weir admits, "has the hardest job in rock'n'roll" in stepping into Garcia's shoes. Added to the brew were two keyboard-players, Rob Barraco, from Lesh's band, and Jeff Chimenti, from Ratdog. The group emerged last year as The Dead and announced an unexpected addition - the singer Joan Osborne, best known for her hit "(What if God Was) One of Us?".
The good news for fans who became disheartened by the comparative lack of adventure displayed in the Dead's final half-decade, as Garcia's drug dependency took its toll in a painful public decline, is that this band is fired with a new-found enthusiasm for no-holds-barred exploration. "We're extending our material a lot more," says Weir, "and we're really jamming hard. Both Phil, with his band, and me, with mine, have got a lot looser and we're feeding that back into The Dead: that's the essential role these bands play."
How does Osborne fit into a group whose musicians, now either approaching or already in their sixties, have been together, in one form or another, for 40 years? "Joan's a game pup, I gotta say. She absolutely gives her all. She's mostly doing old Jerry tunes, but she also throws in the odd song by Pigpen [the Dead's much-missed blues vocalist, who died in 1973]. For a lot of people who haven't seen The Dead, the jury is still out, but those who've caught our shows this summer know that Joan's a real good fit."
And how does he feel now, eight years after the death of his mentor Garcia? "Jerry is in my heart, head and ears all the time. It's as if I can almost see him out of the corner of my eye when I'm on stage. So I don't miss him: he's not gone. I don't think I'm slipping into some hippie New Age philosophy, but it really does feel that we're up there on stage channelling him somehow.
"But whether people come to see The Dead or Ratdog, they can be assured that it's not just a walk down memory lane."
Ratdog play The Astoria, London (020-7344 0044), tonight; Robin 2, Wolverhampton (01384 637747), tomorrow; Canterbury Fayre, Kent (01494 794887), Sunday; The Stables, Milton Keynes (01908 280800), Monday; and Life Café, Manchester (0161-833 3000), TuesdayReuse content