From the first raggy pianola riff cooked up to accompany a Keystone Kops comedy to the orchestral pomp and Top 40 pop blasting out of modern multiplexes, music has been crucial to the cinema. Just try to imagine movies without it: dialogue thudding into dead air, chase scenes devoid of suspense, dramas without crescendo, comedies without punch. In short, movies would seem ordinary. Now, that's not why we go see them, is it?
Or, increasingly, to hear them. The music that tumbles off the screen has more and more often been finding its way onto people's stereos, whether it's the sweeping score of an individual composer, the perennial appeal of a classic musical, or a snapshot of the pop-music moment. In sorting through the hundreds of worthy soundtracks to find the 100 best, we were reminded of how rich, dynamic, and deep is the trove of great movie music. What you'll see here is a tip of the iceberg (speaking of which, Titanic fans, note that we're talking ''best,'' not ''best-selling''). That said, our picks run the gamut, from the groundbreaking orchestrations of King Kong and the Tin Pan Alley swagger of The Band Wagon to the junkie-Top 40 nuggets of Trainspotting and the mountain music of O Brother, Where Art Thou? If you're looking to set up your own movie-music library, here's your chance to know the score.
1 A Hard Day's Night
(1964) It was the G7sus4 heard 'round the world. You may not recognize that chord by name, but you'd instantly know it as the ringing opening salvo of A Hard Day's Night, the soundtrack that turned a nation into a glee club. In 1964, the Beatles had already taken over our radios and TV sets when they decided to commandeer our movie palaces, too. The resulting film was an exhilarating fusion of the backstage musical and postmodern absurdism. To re-create the hysteria that had greeted their Ed Sullivan Show appearances, the Fabs had to come up with tunes that would out-pleasure ''Please Please Me.'' And they delivered, the film's seven classics ranging from the plaintive ''And I Love Her'' to the ecstatic ''Can't Buy Me Love.'' The music stands on its own, yet is forever tied in our imaginations to the filma blitzkrieg of black-and-white imagery that changed the way we see the world. We can't think of a better definition of a great soundtrack.
2 The Sound of Music
(1965) Let's start at the very beginning: Rodgers and Hammerstein's final work first won fans on Broadway. But a better place to start is with the film, in which the tale of singing sibs and their remarkably musical governess in Nazi Austria found its voice in Julie Andrews. If TSOM's rep suffers hipsters' sneers, that says more about our times than the songs. Is there a more inspiring anthem than ''Climb Ev'ry Mountain''? A simpler expression of comfort amid fear than ''My Favorite Things''? A few weeks ago, these earnest themes seemed outdated. Now, this tale of finding joy in a world gone mad is impossible to resist.