One aspect of John Williams’ scores that often goes unnoticed is how long they are—in the case of 1993’s Jurassic Park, his work can be heard in nearly an hour and a half of a two-hour movie. It’s not that the music overstays its welcome. If anything, part of what made the Star Wars and Indiana Jones franchises so successful—and, in turn, made Williams one of the world’s few recognisable film composers—is how much the score drove the movie’s action and sustained its thematic moods. Like his work on Close Encounters of the Third Kind, Jurassic Park is heavy on wonder—a function, in the former, of bearing witness to alien life, and in the latter, to the dinosaurs so miraculously reconstituted on Isla Nublar (“Theme From Jurassic Park”). But it’s also one of Williams’ scariest, most dissonant scores, filled with shrieking strings (“The Raptor Attack”) and roaring brass (“T-Rex Rescue & Finale”) that mirrored sound designer Gary Rydstrom’s uncanny dinosaur sounds. (Not that we know what dinosaurs actually sounded like, but still.) The movie has too much going for it to say that the score carries the action. But where most audiences would understand that the Imperial army of Star Wars or the Nazis of Indiana Jones are bad, the sheer newness of the world Jurassic Park creates left Williams with the tricky responsibility of telling the audience how to feel in a place where we aren’t quite sure what to feel, or when—and whether those awe-inducing dinosaurs see us as strange friends, or just a light snack.