Composer John Adams, winner of this year’s Pulitzer Prize for music, started out as something of a copycat minimalist. But eventually he arrived at a confident style of his own, integrating an expansive sense of harmony reminiscent of late Romanticism and the simple lyricism of American folk songs with minimalism’s driven rhythmic patterns. He’s as comfortable with medieval polyphony as he is with ragtime, and his music is easier on the ear than most modernist works; it’s provided a model for the pop-inflected eclecticism favored by many of today’s younger composers. He’s also as canny at gauging what might interest the public as Verdi was, a talent evident in his headline operas, Nixon in China (a trailblazing parody of East and West stereotypes) and The Death of Klinghofer, inspired by the Achille Lauro hijacking. (His Pulitzer-winning composition, “On the Transmigration of Souls,” is a gut response to the events of September 11.) El Nino, his 2000 oratorio on the Nativity, will have its local premiere at Ravinia today; the title refers not just to Christ but also to the weather phenomenon. In the oratorio, Adams depicts the birth of Christ from Mary’s point of view; the libretto, by Adams and director Peter Sellars, stitches together biblical passages both canonical and apocryphal, verses by Hildegard von Bingen, pronouncements by Martin Luther, and poems by the Mexican nun Sor Juana Ines de la Cruz and other Spanish-language writers. A soprano and a mezzo-soprano alternate as Mary, and a neomedieval trio of countertenors gives running commentary. El Nino was first presented in a multimedia version staged by Sellars and later broadcast on PBS. The semistaged production at Ravinia (under Edward Berkeley’s direction) was mounted by the Atlanta Symphony Orchestra and Chorus in Atlanta two weeks ago. Soprano Heidi Grant Murphy and mezzo-soprano Nancy Maultsby sing Mary; bass-baritone Eric Owens is Joseph. Robert Spano, a specialist in American contemporary music, conducts. Friday, June 6, 8 PM, Pavilion, Ravinia Festival, Green Bay and Lake Cook Rds., Highland Park; 847-266-5100.