Epiphanies happen in our back yard, John Adams succeeds in telling us in ``El Niño: A Nativity Oratorio.'' The ambitious new score, a 21st-century ``Messiah,'' not only succeeds, but is also the composer's most beautiful music yet.

The piece is getting its North American premiere with the San Francisco Symphony, Chorus and a first-class cast conducted by Kent Nagano. If you are able, get to the final performance tonight at Davies Hall.

If not, don't despair. The work, which was unveiled in Paris last month, is going to be around a long time.

While you might not get the opportunity again to see this version with Peter Sellars' imaginative choreography and filmic semi-staging, it wouldn't be a complete loss. Despite some arresting visual moments, the ear, not the eye, held the pleasures Thursday night.

It is always a thrill to hear new music by a good composer. Adams, who also produced ``Harmonium'' and ``Nixon in China,'' is one of this country's foremost composers.

He also is brave. It's enough to attempt the same story in the same format as Handel's ``Messiah,'' still popular after 200 years. And it's remarkable for a politically liberal artist to create art about the birth of Jesus. Adams has said, ``In Berkeley, where I live, if you say you are a Christian, people straighten up and get very nervous.''

``El Niño'' conveys a respect that doesn't drown in sentiment, and it has a grace appropriate to mysteries.

Adams is branded a ``minimalist.'' But the way he uses simple chords and pulsing repetitions has more sophistication, more timbral ingenuity and more melodic invention than more famous proponents of the style such as Philip Glass.

More than minimalist

``El Niño'' is basic, starting in D minor and ending in D Major, and there are pounding moments that remind listeners of minimalist cliches. But it is so much more than that.

The vocal writing is fluid and shows care for the human instrument. Like other oratorios, the soloists -- soprano Dawn Upshaw, mezzo Lorraine Hunt Lieberson and baritone Wilfred White -- alternate characters. Upshaw sings as Mary, but so does Lieberson. Baritone White alternately takes the roles of the confused Joseph and the wrathful Herod. One of the most mesmerizing numbers is his solo ``Shake the Heavens,'' which segues into a heated chorale.

Adams' most brilliant stroke is the use of three countertenors -- Daniel Bubeck, Brian Cummings and Steven Rickards -- as angelic visitors or narrators. The chromatic beauty of their first ``Hail, Mary'' suggests something of the Renaissance aspirations of a Johannes Ockheghem or Josquin des Pres.

Scripture and poems

Unlike minimalist sensation Glass, Adams' music says a lot. The composer's texts include Scripture and poems in a straight-ahead retelling of the birth of Christ. The standouts include a ``Magnificat'' from Luke, which is sung in English, and ``La Anunciación'' (The Annunciation) and ``Speaking of Gabriel,'' both by 20th-century Mexican poet Rosario Castellanos and sung in Spanish. Adams is indebted to Sellars for the choice of Castellanos and another poet, Sor Juana Inés de la Cruz.

He may not be so indebted to Sellars' filmic backdrop, which the director cut to fit the musical score -- a nice reversal to the Hollywood pattern where you make a movie and then write a soundtrack to go with the picture. The film illuminates Adams' shimmering music and drives home his point about epiphanies in our own back yard.

Sellars' film falls flat because the images of L.A. freeways, California beaches, barrios and laundromats last too long. But he has chosen sympathetic faces: cops who cry a Chicano mother with facial piercings.

His choreography is spare and sometimes eloquent. The movements for the dancers in the film were repeated on stage with an agile emotion. After a while, the symmetry piled up and paled. The simple gestures given the singers, especially the countertenors, worked.

El Niño: A Nativity Oratorio

Where: Davies Symphony Hall, 201 Van Ness Ave., San Francisco

When: 8 tonight

Tickets: $28-$80; (415) 864-6000, www.sfsymphony.org