E-Mail This Article to a Friend American beauty The Gardner Museum fêtes Charles Ives BY DAVID WEININGER

Charles Ives is the latest composer to gain entrance into the Birthday Club — those who not only have been admitted to the canon but for whom a significant anniversary is cause for both celebration and studied rethinking. This year marks the 50th since Ives’s death, but so far there have been few local events to mark the occasion.

This Sunday, however, the Isabella Stewart Gardner Museum hosts the first of two programs devoted to various solo, vocal, and chamber works by Ives. (The second will follow next Sunday.) The concerts will be presented by an impressive array of familiar performers that includes baritone Randall Scarlata, clarinettist Richard Stoltzman, violinist Lucy Stoltzman, flutist Paula Robison, and the Borromeo String Quartet.

"For me, he’s a totally unique modern composer, and he’s one of the great modernists, perhaps even a postmodernist," says pianist Jeremy Denk over the phone from New York. Denk curated the series for the Gardner, and he’ll play in every piece. "His music can be chaotic and eclectic and wild."

Those references to chaos and untamed dissonance are by now familiar to our thinking. Ives’s reception has until recently been dominated by appreciation of the shock that his music packs, and he usually stands as the great iconoclast, an outsider to every musical strand of his time. But this year’s reassessments have, among other things, begun to question that maverick status, asking not just about his originality but about how he might fit into some of the traditions outside which he’s routinely assumed to stand.

That’s an approach Denk can appreciate — dig underneath its many layers, the pianist says, and you discover "how simply romantic a lot of the music is." And unlike many modernists of the time, Ives never became self-referential; he retained what Denk calls "the vastness of his vision. He’s in touch with another dimension outside of the music." In terms of the romantic/modernist distinction, "Ives is a neither-nor. That’s why he’s almost a postmodernist."

What’s also becoming clear is that Ives was a first-class musical wit. Hallowe’en, for piano, string quartet, and bass drum (it will be played next Sunday), is a lighthearted depiction of boys dancing around a campfire; there’s an abundance of musical events — in multiple keys and meters — and "every layer is like another log being added to the fire." Denk paraphrases Ives’s remark that the work was a joke that "even Herbert Hoover could get."

Our 31st president could probably also have gotten the humor in the scherzo of Ives’s Piano Trio, but just in case, the composer titled the movement TSIAJ ("This Scherzo Is A Joke"). Ives’s bizarrerie includes asking the cellist to play "My Old Kentucky Home" with a host of wrong notes. "He had a tremendous gift for writing the perfect joke in that way," Denk explains. "But they’re hard to execute in the right ‘wrong’ way — it’s extremely complex."

The core of the Gardner festival is the Concord Sonata, which Denk will perform this Sunday. I ask what goes into preparing a performance of this Olympus of the piano repertoire. "Very many hours," he laughs. "In a way, Ives’s ideas are simpler than they seem at first glance." Thus, what appears to be "a manic improvisation" can be clarified by untangling the seven or eight main motives that are caught up in dense layers of counterpoint. For sheer technical complexity, Denk points to the wild last four pages of the "Hawthorne" movement. "You just have to practice that. It’s one of the most difficult things in Ives."

Even with the attention and explication he’s been accorded lately, Ives still seems too difficult for some listeners. Denk, though, says that he was hooked from his first encounter with the Piano Trio 12 years ago, and that his admiration for the composer’s full body of work has only grown since then. "The more that I play it, the more beautiful it seems to me."

The Isabella Stewart Gardner Museum presents its Ives celebration at 1:30 p.m. this Sunday and next, October 24 and 31. This Sunday’s program will comprise the Largo for Violin, Clarinet, and Piano as well as Songs for Voice and Piano and the Concord Sonata. Next Sunday’s program will comprise Hallowe’en, Sonata No. 3 for Violin and Piano, and the Piano Trio. Tickets are $20 and include museum admission; call (617) 278-5150.