Libby Larsen doesn't need caffeine. Words and ideas tumble out of her, competing for breath, at a pace too quick for note-taking.

Prolific composer, teacher and lecturer, tireless advocate for the new, the diminutive Larsen is one of Minnesota's foremost artists (and one of its leading exports). Statements that, if made by others, might sound pretentious or slightly batty -- "I want to be music," she exclaimed in a recent interview -- seem, when she utters them, sensible and straightforward. She has the gift of being simultaneously down to earth and wildly, unstoppably imaginative.

Improbably, her latest project -- to be unveiled this week by the St. Paul Chamber Orchestra -- had its beginnings at a Twin Cities law firm. Wishing to honor former CEO Lowell Noteboom, the partners of Leonard, Street and Deinard approached SPCO president Bruce Coppock about a commission.

Coppock turned to Larsen. "The law firm had a search committee, and I had to interview with them," she recalled with a chuckle. "It was quite strange. Luckily, I have some experience with depositions." (She's married to a lawyer.)

It was during this interview that she realized her piece "had to be about Lowell contemplating Bach," said Larsen, who knows Noteboom from his long service on the boards of the SPCO, the MacPhail Center and the League of American Orchestras.

"I took delight in hearing his partners describe him as a man of reason, of order, of infinite wit. Bach epitomizes those same qualities, and I said so."

Then Larsen hit the books. "I read everything I could about Bach, with more of a cultural than a technical perspective. Eventually I stumbled upon James Gaines' extraordinary 'Evening in the Palace of Reason'" -- a 2005 book that discusses a famous encounter between Bach and the Prussian monarch Frederick the Great on May 7, 1747.

"Gaines situates Bach at the crossroads of the age of faith and the age of enlightenment," Larsen said. "And in contemplating Bach at that crossroads, we can contemplate some of the tensions in our own culture, a culture very much at odds with itself. For Bach, music was a fundamental organizing principle; it served the being, the essential nature, of humankind. But for Frederick, music was an entertainment, a diversion -- a lot like the Roman Colosseum, or the Super Bowl. It served the state, just as it now serves commercial interests or an imagined oneness."

Gaines, who allowed Larsen to use his title, gave her the springboard she needed. "I decided," Larsen said, "to create my piece in much the same way that Bach created 'The Musical Offering' " -- the work that, as Gaines recounts, grew out of Bach's meeting with Frederick.

"The whole piece is built on two themes: the so-called Royal Theme from 'The Musical Offering' and the B-A-C-H motive." (Frederick pressured Bach to improvise a fugue on the first of these themes. The second, corresponding to the pitches B-flat, A, C and B-natural, is the composer's oft-used musical signature.) Larsen's commission called for a piece for strings; she decided to set a string quartet against the larger string body, in the manner of the baroque concerto grosso.

Counterpoint (the technique of layering different melodic lines) looms large in Larsen's score. "With Bach," she said, "you can't avoid counterpoint. Midway through the writing, I realized how much I love it, although it's fallen away from the common musical ear. Counterpoint is a culture's reflection on itself. If only our own culture could be more contrapuntal!"

Is the music of "Evening," with all its historical references, a bit of an insider's game, its intelligibility dependent on the listener's erudition? Larsen thinks not.

"You don't need to know anything about Bach to engage with his music or with mine," she said. "The only prerequisite is close attention."

Larsen's current projects include an opera, two string quartets and a bassoon sonata. (To compose the latter, she's "trying to understand what a giraffe would say if it could make sound.") Yet busy as she is, she's troubled by much of what she sees around her.

"Classical music today is mainly a repackaging industry," she mused. "I'm no longer sure what its purpose is. A composer can make pieces that work well within the industry's standards, and many do. But music is so much more fluid than that. Nobody owns it -- not the composers, not the packagers. More and more, I want it to go where it needs to go. The longer I dwell with music, the more I'm humbled by its generosity."

Larry Fuchsberg writes frequently about music.