The jazz pianist fuses past with present on a tribute CD featuring Joni Mitchell, Stevie Wonder and Kathleen Battle.

It was not, Herbie Hancock says, his idea. Not his idea, that is, to make Gershwin's World, his new CD tribute to George Gershwin occasioned by the centenary of the American composer's birth. The concept does seem a bit obvious - so obvious in fact that Gershwin tributes are almost a dime a dozen in 1998.

Hancock, on the other hand, has made a career - now in its 40th year - of avoiding the obvious.

Think of his work in the mid-1960s with Miles Davis's fable jazz quintet: "each night on any given tune," the pianist remembered, "we'd create a whole new way of doing it." Think of his venture into funk-fusion with Headhunters in the early 1970s, and still further into techno-funk with his 1983 hit Rock-it. And think of his 1996 CD, The New Standard, in which he reworked songs by Kurt Cobain, Peter Gabriel and Simon & Garfunkel for a stellar cast of jazz modernists.

No, the idea for Gershwin's World came from the CD's producer, Robert Sadin."The concept he had," Hancock explained, "was that each piece would have a different setting, with different musicians. And that's what interested me. I could use them to find other ways of re-examining convention - of re-examining what people might expect me, as a jazz musician, to do."

And so Hancock, in his way, has once again been able to avoid the obvious. Meanwhile, his record company, Verve, clearly expects Gershwin's World to do very well - well enough to make it worth getting the pianist out of Los Angeles for the two-week promotional tour that brought him to Toronto, direct from Europe, earlier this week. An in-store appearance at BMV on Yonge Street drew more than 300 fans from all periods of his career: Hancock - neither tall nor short, a trim figure at 58 in matching brown, pin-striped shirt and slacks - did a round of media interviews the next day.

Make no mistake, even if the CD wasn't his idea, he does love Gershwin. "First of all," he noted, talking with yet another visitor to his suite at the Kind Edward Hotel, "Gershwin's melodies are really endearing and enduring. And harmonically, he captures a felling that's timeless."

Of course that hasn't stopped Hancock from tinkering with Gershwin, much as he tinkered with Cobain et al on The New Standard.

"Well, it's my album," he explained, a bit possessively but with a smile. "I wanted to put my stamp on it, my personality. One of the things I like to do is restructure chords - 'reharmonize' is the word we use. I enjoy doing that. And also, because people know these tunes so well, and because they've heard them played in a much more standard fashion for so many years, I wanted to breathe a new kind of freshness into them"

But he didn't stop there in his effort, as he put it, "to carve a niche for Gershwin - and for myself." Scattered among the CD's 14 tracks are pieces by four of Gershwin's contemporaries, W.C. Handy, James P. Johnson, Duke Ellington and Maurice Ravel. The second movement of Ravel's Concerto for Piano and Orchestra in G finds Hancock in the role of classical pianist, as does Gershwin's own Lullaby, both performed with the Orpheus Chamber Orchestra.

And then there is the matter of Gershwin's most popular songs, with lyrics by brother Ira. "People would expect me to use jazz singers. And just because that was expected, I thought, No, let's not use jazz singers," Instead, Hancock called Joni Mitchell, Stevie Wonder and Kathleen Battle - a Canadian folkie, an icon of soul music and a classical diva, respectively.

But irony of ironies, Mitchell - who recorded The Man I Love and Summertime the very same day that Hancock invited her to appear on Gershwin's World - sounds like the very archetype of a post-Billie Holiday Jazz singer. She's almost unrecognizable as our Joni.

And what went through Hancock's mind when he heard her in this new and unlooked for guise? "I was just as shocked as everybody else who's heard this record. It was amazing."

Even if Mitchell's transformation wasn't quite what Hancock might have expected, or indeed intended, he could hardly object to her willingness to risk stepping completely out of character. He was gone against type often enough himself. After all, it's a long way from Hancock's elegant 1960s jazz themes Maiden Voyage and Dolphin Dance to the fractions Rock-it.

He called Mitchell a "risk-taker." Later, he used the term to describe himself.

"I don't think much about what other people think of me," he commented, of the reaction that has greeted some of his creative decisions over the years. "I do what I think is right. I'm interested in exploring, I'm interested in learning. I try to keep an open mind about things. That's what makes life exciting for me."

All of which will give any musician who decides to make Herbie's World in 2040 - the centenary of Hancock's Chicago birth - plenty to work with. For his part, Hancock has little advice to offer at this still early date, apart from a helpful list of the W.C. Handys, James P. Johnsons and Duke Ellingtons in his own life. "My influences - in the same way I included Gershwin's World - are people like Miles Davis, Bud Pwell, Gershwin, Ravel, Stravinsky, Wayne Shorter ..."

Beyond that, anyone intent someday on honoring Hancock as Hancock has now honored Gershwin would do well to remember this piece of self-assessment, one offered in the context of Gershwin's World but useful in any consideration of the pianist's entire career. "I'm not the kind of guy who wants to be stuck in the past, but I'm not the kind of guy who want to forget it, either."