As I watched three musicians mount the stage at The Willow, a dimly lit Somerville jazz club, the words to Gershwin's "Nice Work If You Can Get It" ran through my mind. Nice work. But only if the musicians and we, the audience, "can get it." ¶ The three musicians -- guitarist Joe Morris, saxophonist Joe Maneri, and Maneri's violinist son Matt -- most likely wouldn't perform Gershwin, though; free jazz from their recent "Three Men Walking" CD was the expected fare. ¶ The next ninety minutes were an unexpected feast for mind and heart as the trio executed daredevil music, a chaotic-sounding yet cohesive blend of dashing violin swoops, delicate guitar filigree, and wailing sax runs. Although they offered tunes from their recording, they were rethinking them, altering phrasing and rhythm, interrogating themselves, measure by measure, about what they wanted the tunes to communicate. Now.

People who are unfamiliar with jazz improvisation might not "get it." They might stereotype this disorderly sounding improvised music as a formless free-for-all of impulsive self-expression. But as jazz musicians know, it is usually the opposite. "I used to think, 'How could jazz musicians pick notes out of thin air?'" wrote bassist Calvin Hill about his apprentice days. "I had no idea of the knowledge it took. It was like magic to me at the time."

To see Morris and the Maneris interact was to peer into the heart of improvisation. They began sitting in a semicircle. A playlist was passed among them, briefly discussed, then tossed aside. While the guitarist and violinist remained seated throughout, their eyes darting from instruments to one another, the saxophonist occasionally let a long-held bass note lift him out of his chair. Standing, slightly swaying, he would look at his son, then Morris, then away from both, at the audience, but also beyond us, gazing at that eternity where the old jazz saxophone ancestors dwell.

To follow the musicians' gazes and notes was a challenge. But it yielded the insight that improvisation is the art of constantly shifting one's perspective -- and constantly tinkering with the language for communicating perspective shifts. It is the art of interacting with others in a manner that constantly alternates leader and follower roles. The goal is to collectively create memorable products that reflect the past, while inventing the future.

Most of all, improvisation is the art of knowing how and when to transcend one's traditional thought and work patterns. Playing without a net has its pitfalls; even musical masters have dry spells. But musical highpoints make the occasional disappointments forgettable. Improvisational work becomes a riveting journey into the unknown, when shopworn approaches are tossed aside and perspective shifting becomes a necessity, to stay communally "in tune."

Norman Weinstein is a poet and critic whose most recent book is A Night in Tunisia Imaginings of Africa in Jazz.