In the beginning, there was film. And sound. The two have been inseparable for roughly a century.

But wait -- the first movies were silent, and "talkies" only arrived in the late 1920s, so what's this about a century of sound and film?

It's simple.

"Silent films were never silent," says composer and conductor John Williams, whose memorable film scores have earned him five Oscars. "There was always music to go with them."

Once sound-on-film became possible, the marriage of the visual and aural arts blossomed even more, producing an extraordinary musical legacy. During a 10-day festival starting Thursday at the Kennedy Center, the National Symphony Orchestra will offer audiences an opportunity to explore that legacy.

"Soundtracks: Music and Film" will include extensive repertoire, from the first film score written by a major classical composer (Camille Saint-Saens in 1908) to some of Williams' most popular movie music (E.T., Jaws, Raiders of the Lost Ark, etc.). But that's just part of the picture. "As far as I know, this is the most extensive festival of its kind," says Williams.

Inside the process

One of the concerts -- "In Synch: How Do They Do It?" -- will let listeners in on the actual mechanics of matching music and image, right down to "click tracks," "streamers" and "mickey-mousing." On that night, providing this insider's guide to film scoring will be Williams, NSO music director Leonard Slatkin and film director Stanley Donen (Singing in the Rain, Charade, et al.).

"I don't think something like this -- how music has been put into film -- has ever been done before in the context of a concert situation," Slatkin says.

Another program will look at European film scores by such eminent composers as William Walton and Dmitri Shostakovich. And on another night, Fritz Lang's iconic 1926 silent film Metropolis will be shown while the orchestra plays a new score assembled by John Goberman from music by Grieg, Bartok and Schoenberg. Lectures and panel discussions will complement the performances, offering deeper looks into various aspects of film music and addressing such topics as Hollywood vs. Washington during the McCarthy Era.

Incorporating the world of movies, let alone a technical program like "In Synch," into an orchestra's regular subscription series is in itself a novelty. "I want to put film music in a different light, away from the pops programs where it usually gets placed," Slatkin says, "and treat it much the same way as we do excerpts from ballet or opera."

"Leonard has a personal feeling for what goes on out here," says Williams, Slatkin's co-artistic director for "Soundtracks," from his California home. "He has a special interest in film music. Both his parents, who I knew and worked with a lot, were in studio orchestras. His father [Felix Slatkin] was concertmaster at 20th Century Fox when I played in the orchestra. I played my first film score with him; I think it was South Pacific."

Slatkin's mother, Eleanor Aller, was principal cellist for the Warner Brothers orchestra. During last year's NSO festival, "Journey to America: A Musical Immigration," Slatkin led a program that included music from Erich Wolfgang Korngold's score for the Bette Davis / Paul Henreid movie, Deception ; the cello solos on the original soundtrack were played by Aller.

Slatkin's affinity for this Hollywood milieu obviously runs deep. So does his affinity for Williams. "But I am not doing this festival because I had a Hollywood background," Slatkin says. "First, I'm doing it out of respect for John. Second, out of respect for what the motion picture industry has produced for music."

The opening program for "Soundtracks" will be devoted entirely to Williams' works, but not just for the movies. Some of his concert works, including a bassoon concerto called The Five Sacred Trees, will be included, too. (The composer will conduct the music on Thursday; when the same program is reprised on the last day of the festival, Slatkin will do the conducting.)

"I was one of the first persons to do John's concert works when people thought of him as only a film composer," Slatkin says. "His concert music has a real identity that comes through most persuasively. People forget how gifted he is; he has his own language, his own voice."

Composers by coast

On another program, Slatkin and Williams will take turns on the podium. "I do music by the East Coast group -- Aaron Copland and Leonard Bernstein, who went to L.A. to do some film writing," Slatkin says. "John does composers who settled out there -- Alfred Newman, Max Steiner, Bernard Herrmann."

Those last three, and other giants of film music from Hollywood's glory years of the 1930s through the '50s, remain dear to Williams. "So many of them I knew as a young man," he says. "I will show a film clip to begin my half of that program, something I prepared for the Academy Awards show this past year. It's only about five minutes long, but it covers 20 composers, a high-speed romp through the Golden Age of film music. Younger members of the audience will not know many of them, but they're the ones whose broad shoulders we all stand on."

Williams is contributing some new film music for the festival, but don't expect it to sound like the lush, vivid scores he has written for one Steven Spielberg blockbuster after another. It's a piano duet that he and Slatkin will play on the "In Synch" program to accompany some silent film footage.

"In the early days, someone would sit at the piano or organ and improvise something to go with the film, or grab themes from the standard classical repertoire," Williams says. "I thought it would be fun for the audience to get a sense of what that was like. I wrote out this little duet to go with a three-part section of film -- the first part is jeopardy, with the lady tied to the railroad track; the second, lovers in the desert; and third, the chases and pie-throwing associated with comedic films of the time. It's what we might have seen in 1910 and what we might have heard played on an upright piano. Leonard will play the bottom part; I'll play the top part."

Master of the genre

With more than 80 film credits, including the recent Catch Me If You Can, Williams is widely recognized as the leading contemporary master of the genre. "You need to have good facility to be a film composer," he says. "There isn't time for writer's block. You need to write two minutes of music a day, on average, and anyone who knows how many notes go into two minutes will know how difficult that is. And the orchestra is playing the score when the ink -- to put a cliche on it -- is still wet."

For Williams, the process of composing for a film starts with asking, "What should it sound like and what can [the film] tolerate?" The finished score must then satisfy a lot of other people on the production end of the project. "The director comes closest to having autonomy, but it's more complicated than that," Williams says. "Basically, anyone with an ego shouldn't become a film composer."

Despite those five Oscars, along with 17 Grammys, three Golden Globes and a slew of other honors, Williams is anything but egomaniacal, which no doubt explains why he remains such a favorite in Hollywood.

"People ask me what my favorite film score is, and all I can say is, 'This aspect of that score is very good, and maybe another aspect of another score.' You look back months later and think, 'That could have been much better.' But there's nothing you can do. My character is such that I am never entirely satisfied. I just don't take great satisfaction in my work. If I did, I would get more joy out of it."

The public doesn't seem to have any trouble enjoying his work, of course. And more audiences are being exposed to his non-movie scores. In recent years, the Boston Symphony Orchestra, the Cleveland Orchestra and the London Symphony have premiered his concertos and other pieces. Current commissions include a horn concerto for the Chicago Symphony and something for the Los Angeles Philharmonic to play next fall in its new Walt Disney Concert Hall. And there's even talk of an opera, which would be his first, for Placido Domingo and the Los Angeles Opera.

Bit by bit, the condescending attitude toward film music in traditional classical circles may be fading. Not that Williams worries about the way he and other film composers are perceived. "I can't give it much time," he says. "But I'm old enough to have seen a lot of thawing in this. When I was a student there were no courses in film composing; now almost all schools have them. Even students who have no interest in writing for film recognize it as something they want to know about."

For Slatkin, the "Soundtracks" festival is clearly an effort to continue this process of affirming the value of movie music. "Many people don't take it as seriously as I believe it should be taken," the conductor says. "There are points to be made about music and film. It is such an active part of our culture. I don't know if we'll change anyone's mind, but I think audiences will enjoy a break from the overture-concerto-symphony routine. It will be tough on the orchestra; we're covering a lot of material in a short span of time. It's an ambitious festival. But all the festivals we do are ambitious."

'Soundtracks' highlights

7 p.m. Thursday and 8 p.m. Feb. 1: "A Portrait of John Williams"

1:30 p.m. Friday: "Music and Film Made in Hollywood, U.S.A."

8 p.m. Saturday: "In Synch -- How Do They Do It?"

7 p.m. Jan. 30: "The European Aesthetic"

8 p.m. Jan. 31: Live orchestral accompaniment to Fritz Lang's Metropolis

All performances are at the Kennedy Center Concert Hall, 2700 F. St. N.W., Washington. Tickets are $19 to $69. Call 800-444-1324 or 202-467-4600.