When he was recently contacted at his home in Berkeley, California, John Adams was deep into revising his opera Doctor Atomic for future performances in Chicago, Amsterdam, and New York, well after its 2005 world premiere in San Francisco.

"There's one character I think wasn't fully developed, and I'm trying to find a way to write more material and develop her," he says candidly. "It's hard, because once you've written stuff already, it's tough to go back and put new material in it and have it be part of the same genetic structure."

It's with that level of commitment that Adams, one of America's greatest living composers, has succeeded in creating imaginative, lively, and organic structures that grab your ears. When the American Composers Orchestra celebrates Adams's birthday at Carnegie Hall on April 27, the audience will be able to take a big dip in the ocean of that imagination.

"This is a kind of farewell concert that wraps up my residency here at Carnegie Hall," the composer explains of the event, which is titled An Adams Apple: John Adams at 60. Adams has held the Richard and Barbara Debs Composer's Chair for the past four years, a position he has used to conduct "creative process" discussions with such figures as Frank Gehry and to curate concerts highlighting new voices, not only in the classical domain, but in jazz and world music as well.

"If I left any legacy," says Adams of his experience at Carnegie Hall, "it was using Zankel Hall as a venue for a new breed of creative person: composer-performers who just don't sit back and wait for a commission from the Philharmonic or the Met to get their music out."

For the April 27 concert, Adams will conduct three of his own compelling works that have not been heard in New York in years: My Father Knew Charles Ives, The Wound- Dresser, and the Violin Concerto.

The Wound-Dresser (1989), the earliest of these, is a profoundly moving setting of a Walt Whitman poem that recalls the poet's heart-wrenching experiences as a nurse during the Civil War.

"One turns to me his appealing eyes‹poor boy! I never knew you," writes the poet. "Yet I think I could not refuse this moment to die for you, if that would save you." Other stanzas in Adams's piece are more graphic but just as poignant. Eric Owens, the richly endowed bass-baritone who sang important roles in Doctor Atomic and Adams's most recent opera, A Flowering Tree, will sing the elegiac text.

Regarding the most recent work on this month's program, a full disclosure is in order: Adams's father didn't really know Charles Ives. There was a small window of time when, theoretically, his father could have bumped into the overly creative insurance salesman in New England. But Adams's three-movement piece is really about his intimate connection with Ives, the original American Original who consciously snipped the apron strings of Eurocentric classical music.

In fact, Adams refers to his 2003 composition as "musical autobiography, an homage and encomium to a composer whose influence on me has been huge." Keep in mind that both composers received their first musical training from their fathers (Adams's Gnarly Buttons explicitly celebrates this fact, prominently featuring the instrument he learned to play from his dad: the clarinet).

The first movement of My Father Knew, titled "Concord," comes into being with a few otherworldly Ivesian chords, above which a trumpet hauntingly floats‹a reference to Ives's The Unanswered Question. A little later, musical mayhem breaks loose when it seems that two different marching bands are crisscrossing‹an Ives signature moment of controlled chaos if there ever was one. Adams taps into another memory of playing in bands as a kid with his father in the second movement, "The Lake," a lazy, hazy summer nocturne with a crazy mirage of a distant dance band.

In the third section, "The Mountain," that ghostly trumpet from "Concord" returns. What's extraordinary about this final movement is that we hear Ives morphing into Adams right before our very ears. Adams is declaring a direct lineage from Ives though pure sound, as the music evolves from uncanny pastiche to vintage Adams, pulsating harmonies and all. There's no anxiety of influence here. Adams is clearly about the joy of influence.

"Ives's music, for all its daring experiments in rhythm and polyphony, always mixed the sublime with the vulgar and sentimental, and he did so with a freedom and insouciance that could only be done by an American," Adams notes in the booklet accompanying the recent Nonesuch recording of My Father Knew Charles Ives. "This has always been a model for me."

There are Ives-inspired stretches throughout Adams. In his Violin Concerto, written in 1993, the middle movement is a shocking chaconne. Because of certain textural features, and the feeling of different sound masses proceeding at different speeds, you could whimsically call it "When Pachelbel Met Ives in Haight-Ashbury," a neighborhood in San Francisco where Adams lived right after escaping from New England to reinvent his maxi-minimalist self.

The concerto represents a breakthrough in the melody department for Adams, for whom harmony and rhythm had been the primary driving forces up to that point. Adams describes his debut in the concerto format as a study in "hypermelody" in which the violin sings constantly throughout the piece.

"The concerto starts as a mysterious fog that evaporates into a groove tempo," says Leila Josefowicz who will be this month's soloist on the work. "That serves as a platform for my pseudo-Miles-Davis-and-John-Coltrane improv. In the second movement, the violin is a dream that floats above the orchestra, a bit disturbingly. And the last movement is basically a party."

Robert Hilferty is a frequent contributor to Playbill.