By Mark Swed

William Bolcom's oratorio-like Songs of Innocence and Experience isn't often performed. It's a huge work, scored for massive and diverse forces, some--a rock guitarist who can read--not always easy to find. A setting of William Blake's 46-poem, two-part cycle, the score is nearly three hours long, covers an exhaustive emotional range, and traverses just about as many musical styles as there are songs. It taxes listeners, performers, and presenters, whose budgets it breaks.

Yet the vast majority of those who encounter it are simply bowled over. Though based on poetry by a late 18th-century English visionary, Bolcom's masterpiece feels like modern America in a nutshell. When a Naxos recording was released two years ago, it proved an immediate sensation. The three-disc bestseller landed on all the worthwhile year-end lists and won four Grammys, including that for Best Classical Recording. Had Bolcom, who worked on the score, on and off, for a quarter century, completed nothing else, he still would deserve a place in the pantheon of great American composers, to say nothing of being honored as Musical America's Composer of the Year.

But Bolcom has produced plenty during the years of the cycle's composition and since its premiere in 1984. He is especially noted for his hundreds of songs (including the hilariously immortal "Lime Jello Marshmallow Cottage Cheese Surprise"). His operas number three (with a fourth well under way). He has just finished his Eighth Symphony (a Boston Symphony commission for next season). The catalogue continues with cabaret and theater pieces and two film scores, numerous chamber works, an assortment of concertos and concerto-like scores, and diverse pieces for orchestra. His solo piano music is extensive, replete with rags and piano etudes that have become concert favorites.

He has co-authored a book on the ragtime legends, Noble Sissle and Eubie Blake. If you've ever heard him play, you'll not likely forget him as an arresting virtuoso pianist, whether accompanying his wife, mezzo-soprano Joan Morris, or taking the dazzling solo in his way-out Piano Concerto. On the faculty of the University of Michigan, Ann Arbor, since 1973, Bolcom has been mentor and champion of a great many young composers.

Equally diverse and distinguished are Bolcom's own champions. Among conductors, they boast Dennis Russell Davies, Leonard Slatkin, and James Levine. Singers are regularly drawn to Bolcom, among them the stellar Marilyn Horne and Ben Heppner. Bolcom's flamenco-tinged Canciones de Lorca for tenor and orchestra was written for Plácido Domingo and Carl St.Clair's Pacific Symphony to celebrate the opening of the Renée and Henry Segerstrom Concert Hall in Costa Mesa, California. There is a good chance that it is the most effective piece written for the tenor over his long career.

Bolcom is a storied master of many musics. An eclectic's eclectic, he is a composer with something for everyone, whether your taste runs to probing dissonance, country and western, Mozartean neoclassicism, Monteverdian madrigals, Messiaenic ecstasy, mundane music hall song and dance, hard rock, soft rock, soft shoe, swing, early Americana, or Broadway musicals (past, present, and probably future). Songs of Innocence and Experience--which accommodates all of the above and then some--ends with the most glorious reggae this side of Bob Marley.

The exhilarating eclecticism attracts attention, especially given Bolcom's encyclopedic references to popular culture. Like Missus Bell's creation of the week in "Lime Jello Marshmallow Cottage Cheese Surprise"--shrimp salad tossed with chocolate sauce and garnished with a leek--his combinations can take the breath (if not the appetite) away.

But Bolcom's music is more than the sum of amusing, startling, alluring parts. Multi-stylism will get you somewhere, but not everywhere, in modern music. We return to such promiscuous 20th-century mixmasters as Mahler, Ives, Schnittke, and Bernstein for their voice, not their voices. Bolcom's voice, likewise, is distinctive. I know people who couldn't care less about Joplin's "Maple Leaf Rag" but can't get Bolcom's insinuating "Graceful Ghost," a rag he wrote in memory of his father, out from under their skin. The recording by Paul Jacobs is essential to any American music discography.

Bolcom came by his eclecticism in an interesting way. He was born in Seattle in 1938, the year a young John Cage arrived at the Cornish School, the region's high-minded and unusually open-minded arts academy. Cage's progressive percussion music, electronic sounds, and prepared piano proved the talk of the town. The Pacific Northwest of Bolcom's youth was an intriguing atmosphere of Pacific Rim cosmopolitanism and acceptance, was as open to influences from the East as the West, and provided a haven for outsider painters, poets, and artist-inventors.

Seattle gave Bolcom little tolerance for hierarchies. He has said that although he had no desire to follow in Cage's footsteps, the example of an uncompromising composer so comfortable in his own skin gave Bolcom the permission to do what he felt was musically right, which was to oppose the 12-tone dogmatism of the time. Bolcom turned to other eclectics, particularly Darius Milhaud at Mills College in Oakland (a sort of sister to Cornish). A time in Paris and a friendship with Luciano Berio, whom Bolcom considered a populist in a serial wolf's clothing, opened his ears to further possibilities.

But perhaps the greatest influences on Bolcom were his friend and collaborator, the playwright, poet, and librettist Arnold Weinstein, and Joan Morris, whom he met in 1972 and married in 1975. Theater was the obvious model for Bolcom to combine his many musical and literary interests (Blake has been a life-long obsession; the modernist, stream-of-conscious, Seattle-based poet, Theodore Roethke, was a mentor). Together, Bolcom and Weinstein began by making experimental theater pieces in the early '60s and eventually collaborated on cabaret songs and three operas for Chicago Lyric Opera--McTeague (1992), A View from the Bridge (1999), and A Wedding (2004), the sources being, respectively and eclectically, Frank Norris's classic American novel, Arthur Miller's classic American play, and Robert Altman's classic American film.

Bolcom credits Weinstein and Morris with helping steer him toward directness and clarity--the prickly, brilliant lyricist insisting on singable text in which everything can be understood and the mezzo famed for making every word speak. This sense of clarity is a hallmark of everything Bolcom writes, including the instrumental music. His style is the drama of styles interacting as if they were characters in a play, which makes his instrumental music no less theatrical than his music theater.

In his Piano Concerto, written in 1976, he found that in an age of irony he could not celebrate the American Bicentennial with a straight face. Thus Gershwin, Ives, and Copland are admired but not revered, imitated but undercut with biting wit and even flaring anger as a way to keep the American experience genuine, free of pap. The bipolar Fifth Symphony is an ode to love and death, satirical and serious in rapid succession, Messiaen and Wagner put into the grinder, coming out weirdly sexy and scary.

In the end, Bolcom is a natural. He gravitates toward a wide range of musical styles and eras with a restless eagerness that regularly leaves a listener dazzled and even a little dazed. But he's not a mimic. A Bolcom blues or a Bolcom ballad is all Bolcom, readily welcomed into his operas, symphonies, concertos, sonatas, and cabaret scores. He writes in many tongues but one grandly all-American voice. You can never predict what a Bolcom piece will sound like, but you will always know it is his.

Mark Swed is music critic of the Los Angeles Times.