Except for a few academic burps in the middle years of this century, it hasn't been a bad millennium at all. Yet the classical music world has been in a millennial mood for almost a century, and never more so than now, as we embark on the penultimate season of the 20th century.

Just look at the thematic titles on the season fliers: The Choral Arts Society of Washington will present "The 20th Century: Our Legacy for the Future," the 20th Century Consort offers "A 20th Century Retrospective," the National Symphony Orchestra is devoting itself, in part, to a season of "Millennium Programming," and the New Dominion Chorale, which will brook no end-of-century pessimism, is offering a hybrid "Holiday-Millennium" celebration in late December. The Kreeger Museum has even commissioned New York composer Robert Kapilow to cruise the town, hold focus groups and gather material for a work that will be premiered as part of its "DC Citypiece: Monuments at the Millennium" series.

A little reflection on our own troubled century isn't a bad idea at all. The American orchestra, which tolerates the occasional world premiere, seems uninterested in the challenging musics of 30, 50 or 80 years ago. Ironically, it's easier to hear new music than Schoenberg. The New Music Consort will partially remedy the problem by shifting its usual emphasis on new works to devote more attention to the pioneers of today's eclectic musical vernacular. A handful of benchmark works of the century fill out the Consort's first two concerts. Stravinsky's deeply problematic yet enduringly popular "A Soldier's Tale" (Oct. 2) makes an interesting contrast to Schoenberg's "Pierrot Lunaire" (Nov. 13)--two works that mix narrative with unconventional chamber ensemble, with results so vastly different they seem to belong to different worlds. The Consort complements these two, now mostly domesticated early 20th-century works, with music of George Crumb (Oct. 2) and Paul Schoenfield and Hindemith (Nov. 13).

Other ensembles will contribute to the history lesson as well. Da Camera, a chamber group from Houston that treats chamber music as the intellectual equivalent of any other kind of music (which it is), brings Messaien's "Quartet for the End of Time"--a wrenching distillation of everything that went wrong in Europe 60 years ago--to the Library of Congress (Oct. 30); the Juilliard Quartet appears there with music of Bartok (Dec. 17) and Webern (Oct. 7-8). The Choral Arts Society opens its historically self-conscious season with two of the century's great choral masterpieces, Stravinsky's "Symphony of Psalms" and Poulenc's Gloria, on a program that also includes a world premiere by Mark Adamo (Nov. 21).

National Symphony Music Director Leonard Slatkin is second to none as a tireless advocate for music from our own troubled era. He begins the orchestra's regular subscription season (Sept. 23-25) with a representative program of 20th-century works that might leave one with the impression that there's never been a crisis of audience alienation: Ravel's "La Valse," Britten's "American Overture" and John Adams's 1997 "Century Rolls" have snuggled into the canon without protest. Cellist Yo-Yo Ma brings to the orchestra his own exploration of the century on two consecutive evenings (Oct. 1-2), performing music of Arvo Part, Richard Danielpour and John Tavener, all of them masters of so-called "accessibility." The NSO's season opens with the annual Beethoven Festival (Sept. 9-18), this time devoted to an exploration of the concerto repertoire; the most interesting of the programs are on the final weekend, which is devoted to incomplete works, first thoughts and a redrafting of the Violin Concerto for piano.

The Washington Opera, which has no particular millennium agenda, will stage one of this country's undeniable 20th-century achievements: Carlisle Floyd's "Susannah" (Nov. 6-27), an opera that enjoys periodic flirtations with lasting revival, yet always seems a novelty when it returns. Too bad. It's the American opera, not because it's better than all the others, but because it dramatizes the dangers of our national obsession with Old Testament morality: judgmentalism, suspicion and humbuggery. It couldn't make a stronger contrast with the other seasonal highlight, the return of Massenet's overscaled "Le Cid" (Oct. 30-Nov. 22), absent from American opera stages since at least the days of Caruso. The production stars Washington Opera Artistic Director Placido Domingo, who by virtue of making a definitive recording of the role, and reviving it now, is a patron saint of this virtually unknown bit of French grand opera.

The Washington Opera has neither a monopoly on opera nor one on the human voice. The consistently farsighted Vocal Arts Society does its part for the next millennium by cultivating the best of today's young, fin-de-siecle vocalists. The society is concentrating on American singers this season, balancing last year's remarkable roster of European talent. Baritone Nathan Gunn (Nov. 9), who can make a folk song sound like an art song, and vice versa, is not to be missed. Nor is soprano Christine Schaefer's recital (Nov. 17). The operatic event worth clearing the calendar for is Les Arts Florissants' production of Purcell's "King Arthur" (Nov. 6). The ensemble, fresh from celebrating its 20th anniversary, is the world's most consistently interesting, provocative and virtuosic producer of baroque opera.

The Washington area's remarkably vibrant choral community will pay particular attention to Handel this fall. Thomas Beveridge's New Dominion Chorale presents Handel's endearingly bucolic "Acis and Galatea" (Oct. 24); and the Washington Chorus presents the plague-ridden oratorio "Israel in Egypt" (Oct. 29).

Washingtonians can spend the season collecting reminders of soon-to-be-over collaborations. The orchestral world, which is just shaking down from one of its periodic games of musical chairs, is well represented. Claudio Abbado, who will leave the Berlin Philharmonic, brings his orchestra to the Kennedy Center with music of Beethoven and Dvorak (Oct. 16); Seiji Ozawa, now winding down a long and sometimes difficult tenure at the Boston Symphony Orchestra, brings the ensemble to town with a typically robust program of Lutoslawski, Debussy and Brahms (Dec. 11). Mariss Jansons, who conducts the Pittsburgh Symphony, brings his other band, the Oslo Philharmonic Orchestra, with Gidon Kremer and music of Philip Glass and Mahler (Nov. 13); expect the unexpected. All three orchestras are brought here by the Washington Performing Arts Society. WPAS also brings most of the season's exceptional soloists. Pianists of note include Mitsuko Uchida (Nov. 10) and Evgeny Kissin (Dec. 13); violinists include Itzhak Perlman (Oct. 30) and Nadja Salerno-Sonnenberg (Dec. 3).