When it comes to iconic movie themes, the name that pops into most people's heads is John Williams.
Before he composed the score for the first three Harry Potter movies, Williams had written some of the most popular and recognizable film scores of all time. Maybe you've heard some of them? Jaws.Star Wars.Superman. Raiders of the Lost Ark. E.T.Jurassic Park.
Yeah, pretty epic.
So, obviously John Williams was the go-to guy for scoring the first Harry Potter movie. The opening song in that film—"Hedwig's Theme"—is probably the song you think of when you think of Harry Potter. Chamber of Secrets has a lot of the same elements as the first movie and some of the classic John Williams hallmarks.
The film opens with a variation on "Hedwig's Theme" because of course it does. The rest of the score is filled with moments of mischief and mayhem. There's terror in the sounds of slow moving arachnids in "The Spiders" and lots of pomp and circumstance in "Gilderoy Lockhart." The whole score fills the film with either whimsy or worry exactly when it's needed.
Seriously, no one does sweeping, epic scores like John Williams.